Combined drug delivery methods and apparatus

ABSTRACT

Methods and apparatus provide treatment with a first therapeutic agent and a second therapeutic agent for an extended time. The first therapeutic agent may comprise a VEGF inhibitor and the second therapeutic agent may comprise an antiinflammatory, such as a non-steroidal anti-inflammatory, for example a cyclooxygenase inhibitor. One or more of the first therapeutic agent or the second therapeutic agent can be injected into the eye, for example injected into a therapeutic device implanted into the eye to release the injected therapeutic agent for an extended time.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present PCT application claims priority to U.S. Provisional Pat. App. Ser. No. 61/371,168, filed 5 Aug. 2010, the full disclosure of which is incorporated herein by reference.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

Not applicable

BACKGROUND OF THE INVENTION

The present invention relates to delivery of therapeutic agents to the posterior segment of the eye. Although specific reference is made to the delivery of macromolecules comprising antibodies or antibody fragments to the posterior segment of the eye, embodiments of the present invention can be used to deliver many therapeutic agents to many tissues of the body. For example, embodiments of the present invention can be used to deliver therapeutic agent to one or more of the following tissues: intravascular, intra-articular, intrathecal, pericardial, intraluminal and gut.

The eye is critical for vision. The eye has a cornea and a lens that form an image on the retina. The image formed on the retina is detected by rods and cones. The light detected by the rods and cones of the retina is transmitted to the occipital cortex brain via the optic nerve, such that the individual can see the image formed on the retina. Visual acuity is related to the density of rods and cones on the retina. The retina comprises a macula that has a high density of cones, such that the user can perceive color images with high visual acuity.

Unfortunately, diseases can affect vision. In some instances the disease affecting vision can cause damage to the retina, even blindness in at least some instances. One example of a disease that can affect vision is age-related macular degeneration (hereinafter AMD). Although therapeutic drugs are known that can be provided to minimize degradation of the retina, in at least some instances the delivery of these drugs can be less than ideal.

In some instances a drug is injected into the eye through the sclera. One promising class of drugs for the treatment of AMD is known as vascular endothelial growth factor VEGF inhibitors. Unfortunately, in at least some instances injection of drugs can be painful for the patient, involve at least some risk of infection and hemorrhage and retinal detachment, and can be time consuming for the physician and patient. Consequently, in at least some instances the drug may be delivered less often than would be ideal, such that at least some patients may receive less drug than would be ideal in at least some instances.

Work in relation to embodiments of the present invention also suggests that an injection of the drug with a needle results in a bolus delivery of the drug, which may be less than ideal in at least some instances. For example, with a bolus injection of drug, the concentration of drug in the vitreous humor of the patient may peak at several times the required therapeutic amount, and then decrease to below the therapeutic amount before the next injection.

Although some implant devices have been proposed, many of the known devices are deficient in at least some respects in at least some instances. At least some of the known implanted devices do not provide sustained release of a therapeutic drug for an extended period. For example, at least some of the known implanted devices may rely on polymer membranes or polymer matrices to control the rate of drug release, and many of the known membranes and matrices may be incompatible with at least some therapeutic agents such as ionic drugs and large molecular weight protein drugs in at least some instances. At least some of the known semi-permeable polymer membranes may have permeability that is less than ideal for the extended release of large molecular weight proteins such as antibodies or antibody fragments. Also, work in relation to embodiments of the present invention also suggests that at least some of the known semi-permeable membranes can have a permeability of large molecules that may vary over time and at least some of the known semi-permeable membranes can be somewhat fragile, such that drug release for extended periods can be less than ideal in at least some instances. Although capillary tubes have been suggested for drug release, work in relation to embodiments of the present invention suggests that flow through capillary tubes can be less than ideal in at least some instances, for example possibly due to bubble formation and partial clogging.

At least some of the known implantable devices can result in patient side effects in at least some instances when a sufficient amount of drug is delivered to treat a condition of the eye. For example, at least some of the commercially available small molecule drug delivery devices may result in patient side effects such as cataracts, elevated intraocular pressure, dizziness or blurred vision in at least some instances. Although corticosteroids and analogues thereof may be delivered with an implanted device to treat inflammation, the drug delivery profile can be less than ideal such that the patient may develop a cataract in at least some instances.

Although at least some of the proposed implanted devices may permit an injection into the device, one potential problem is that an injection into an implanted device can cause at least some risk of infection for the patient in at least some instances. Also, in at least some instances the drug release rate of an implanted device can change over time, such that the release rate of the drug can be less than ideal after injection in at least some instance. At least some of the proposed implanted devices may not be implanted so as to minimize the risk of infection to the patient. For example, at least some of the proposed devices that rely on pores and capillaries may allow microbes such as bacteria to pass through the capillary and/or pore, such that infection may be spread in at least some instances. Also, work in relation to embodiments of the present invention suggests that at least some of the proposed implanted devices do not provide adequate protection from the patient's immune system, such as from macrophages and antibodies, thereby limiting the therapeutic effect in at least some instances.

In light of the above, it would be desirable to provide improved therapeutic devices and methods that overcome at least some of the above deficiencies of the known therapies, for example with improved drug release that can be maintained when implanted over an extended time.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide therapeutic devices to deliver therapeutic amounts of one or more of a first therapeutic agent or a second therapeutic agent for an extended time to the posterior segment of the eye, for example an extended time of at least about 1 month. The first therapeutic agent may comprise an anti-neoplastic agent, such as an agent to inhibit neovascularization, for example a VEGF inhibitor. The second therapeutic agent may comprise an anti-inflammatory, for example a cyclooxygenase (hereinafter “COX”) inhibitor. While the first therapeutic agent and the second therapeutic agent can be delivered in many ways for the extended time, the therapeutic device may be helpful to reduce the frequency of negative side effects associated with direct intraocular injection such as pain, retinal detachment, hemorrhaging and infection because injections can be made less frequently and can be made into the reservoir chamber of the device rather than into the eye. The therapeutic device can be configured to replace the therapeutic agent when the device is implanted at least partially within the eye of the patient. The therapeutic device may be implanted in the eye so as to extend through the sclera of the eye, and the therapeutic device may comprise a container and a port or penetrable barrier configured to receive a quantity of therapeutic agent. The therapeutic agent can be placed in the container in many ways, for example by placing a solid insert through the port to the inside of the container or by injecting a formulation of the therapeutic agent through the penetrable barrier into the container.

One or more therapeutic devices can be configured in many ways to deliver one or more therapeutic agents for the extended time, such that the patient can be treated with fewer injections. A first therapeutic device may be injected with a first therapeutic agent and combined with injections of a second therapeutic agent into the vitreous humor to treat the eye. Alternatively or in combination, the first therapeutic device may be implanted on or near the pars plana of the eye with a second therapeutic device, and the first device may be aligned with the second device along the pars plana of the eye when the first device releases the first therapeutic agent for the extended time and the second therapeutic device releases the second therapeutic agent for the second extended time. The first therapeutic device may comprise the first therapeutic agent and the second therapeutic agent, such that the first therapeutic agent and the second therapeutic agent can be delivered from the first therapeutic device and the second therapeutic device may not be used in many embodiments. The first therapeutic agent may comprise an anti-neoplastic agent such as a VEGF inhibitor, and the second therapeutic agent may comprise an anti-inflammatory such as non-steroidal anti-inflammatory, for example a cyclooxygenase inhibitor.

In many embodiments, the therapeutic device is configured to provide continuous release of therapeutic quantities of the one or more therapeutic agents for an extended time of at least 3 months, for example 6 months, such that the frequency of injections into the therapeutic device and risk of infection can be substantially decreased. In additional embodiments, the therapeutic device is configured to provide continuous release of therapeutic quantities of at least one therapeutic agent for an extended time of at least 12 months, or at least 2 years or at least 3 years.

The therapeutic device can be configured in many ways to release the one or more therapeutic agents for the extended time and may comprise at least one of an opening, an elongate structure, a porous structure, or a porous surface sized to release the therapeutic agent for the extended time. For example, the therapeutic device may comprise the porous structure to release the therapeutic agent through the porous structure for the extended period. The porous structure may comprise a sintered material having many channels, for example interconnecting channels, extending around many particles adhered to each other. The porous structure may comprise a first side comprising a first plurality of openings coupled to the reservoir and a second side comprising a second plurality of openings to couple to the vitreous humor. The interconnecting channels may extend between each of the first plurality of openings of the first side and each of the second plurality of openings of the second side so as to maintain release of the therapeutic agent through the porous structure, for example when at least some the openings are blocked. The porous structure can be rigid and maintain release of the therapeutic agent through the interconnecting channels when tissue or cells cover at least a portion of the openings, for example when the porous structure is implanted for an extended time and the drug reservoir refilled.

In many embodiments, the reservoir of the therapeutic device is flushable and/or refillable. This provides the added benefit that the physician may remove the therapeutic agent from the patient by flushing the agent from the reservoir of the therapeutic device rather than waiting for the therapeutic agent to be eliminated from the patient. This removal can be advantageous in cases where the patient has an adverse drug reaction or benefit from a pause in therapy sometimes referred to as a drug holiday. The volume of the reservoir and release rate of the porous structure can be tuned to receive a volume of a commercially available formulation, such that the therapeutic agent can be released for an extended time. For example, the volume of commercially available therapeutic agent may correspond to a bolus injection having a treatment duration, for example one month, and the reservoir volume and release rate tuned to receive the formulation volume can extend the treatment duration of the injected volume by a factor of at least about two, for example from one month to two or more months.

In a first aspect, embodiments provide a method of treating an eye having a sclera and a vitreous humor. A first therapeutic amount of a first therapeutic agent is delivered to the vitreous humor of the eye, in which the first therapeutic agent effective for a first extended time. A second therapeutic amount of a second therapeutic agent is delivered, and the second therapeutic agent effective for a second extended time.

In many embodiments, the first therapeutic agent comprises an antineoplastic agent and effective for the first extended time and wherein the second therapeutic agent comprises one or more of a COX inhibitor, a LOX inhibitor, a TNF inhibitor, or an antihistamine.

In many embodiments, the first therapeutic agent comprises a vascular growth inhibitor effective for the first extended time and wherein the second therapeutic agent comprises an inflammatory response inhibitor effective for a second extended time.

In many embodiments, the vascular growth inhibitor comprising one or more of a VEGF inhibitor,

In many embodiments, the inflammatory response inhibitor comprises a cyclooxygenase (hereinafter “COX”) inhibitor.

In many embodiments, the COX inhibitor comprises one or more of a salicylic acid derivative, a propionic acid derivative, an acetic acid derivative, and enolic acid (hereinafter “Oxicam”) derivative, a fenamic acid derivative, a selective COX-2 inhibitor (hereinafter “Coxibs”).

In many embodiments, the inflammatory response inhibitor comprises the propionic acid derivative and wherein the propionoic acid inhibitor comprises one or more of Ibuprofen, Naproxen, Fenoprofen, Ketoprofen, Flurbiprofen or Oxaprozin.

In many embodiments, the inflammatory response inhibitor comprises the acetic acid derivative and wherein the acetic acid derivative comprises one or more of Indomethacin, Sulindac, Etodolac, Diclofenac or Nabumetone.

In many embodiments, the inflammatory response inhibitor comprises the Enolic acid (hereinafter “Oxicam”) derivatives and wherein the Enolic acid derivative comprises one or more of Piroxicam, Meloxicam, Tenoxicam, Droxicam, Lornoxicam, or Isoxicam.

In many embodiments, the inflammatory response inhibitor comprises the Fenamic acid derivative and wherein the Fenamic acid derivative comprises one or more of Mefenamic acid, Meclofenamic acid, Flufenamic acid, or Tolfenamic acid.

In many embodiments, the inflammatory response inhibitor comprises the Selective COX-2 inhibitor (hereinafter “Coxibs”) and wherein the Selective COX-2 inhibitor comprises one or more of Celecoxib, Rofecoxib, Valdecoxib, Parecoxib, Lumiracoxib, or Etoricoxib.

In many embodiments, the first therapeutic agent is injected into the vitreous humor of the eye.

In many embodiments, the second therapeutic agent is injected into the vitreous humor of the eye.

In many embodiments, a container at least partially introduced through the sclera to couple the container to the vitreous humor and the sclera.

In many embodiments, the first therapeutic agent is injected into a chamber of the container when the container is coupled to the vitreous humor and the sclera and wherein the container is configured with a porous structure and a volume to release the first therapeutic amounts of the first therapeutic agent from the chamber into the vitreous humor for the first extended time.

In many embodiments, the second therapeutic agent is injected into a chamber of the container when the container is coupled to the vitreous humor and the sclera.

In many embodiments, the first therapeutic agent comprises a VEGF inhibitor and the second therapeutic agent comprises a cyclooxygenase inhibitor.

In many embodiments, the cyclooxygenase inhibitor comprises a solid coupled to the container to release the second therapeutic agent for the extended time.

In many embodiments, the solid cyclooxygenase inhibitor is located within the chamber of the container and released through the porous structure.

In many embodiments, the solid cyclooxygenase inhibitor is located within a second chamber of the container and released through a second porous structure.

In many embodiments, the second chamber is separated from the first chamber.

In many embodiments, the second chamber is coupled to the first chamber with the first porous structure and coupled to the vitreous with the second porous structure such that the first therapeutic agent passes through the first porous structure and second porous structure to reach the vitreous humor.

In many embodiments, the solid cyclooxygenase inhibitor is located away from the chamber and coupled to the vitreous humor.

In many embodiments, the container is configured to release the therapeutic amounts of the first therapeutic agent into the vitreous humor for the first extended time.

In many embodiments, the first therapeutic agent comprises a vascular growth inhibitor effective for the first extended time and wherein the second therapeutic agent comprises a lipoxygenase pathway (hereinafter “LOX”) inhibitor effective for the second extended time.

In many embodiments, the LOX inhibitor comprises a 5-LOX inhibitor.

In many embodiments, the first therapeutic agent comprises a vascular growth inhibitor effective for the first extended time and wherein the second therapeutic agent comprises an antifibrotic agent effective for the second amount of time.

In many embodiments, the first therapeutic agent comprises a vascular growth inhibitor effective for the first extended time and wherein the second therapeutic agent comprises a tumor necrosis factor (hereinafter “TNF”) inhibitor effective for the second extended time.

In many embodiments, the TNF inhibitor comprises pentoxifylline effective for the second extended time.

In many embodiments, the first therapeutic agent comprises a vascular growth inhibitor effective for the first extended time and wherein the second therapeutic agent comprises a dual COX/LOX inhibitor effective for the second extended time.

In many embodiments, the dual COX/LOX inhibitor comprises Licofelone.

In many embodiments, the first therapeutic agent comprises a vascular growth inhibitor effective for the first extended time and wherein the second therapeutic agent comprises an antihistamine.

In many embodiments, the antihistamine comprises azelastine.

In many embodiments, the antihistamine comprises an H1-receptor antagonist.

In many embodiments, the H1-receptor antagonist comprises one or more of Clemastine, Diphenhydramine (Benadryl), Doxylamine, Loratadine, Desloratadine, Fexofenadine, Pheniramine, Cetirizine, Ebastine, Promethazine, Chlorpheniramine, Levocetirizine, Olopatadine, Quetiapine, Meclizine, Dimenhydrinate, embramine, dimethindene, or dexchlorpheniramine.

In many embodiments, the antihistamine comprises an H2-receptor antagonist.

In many embodiments, the H2-receptor antagonist comprises one or more of Cimetidine, Famotidine, Ranitidine, Nizatidine, Roxatidine, Lafutidine.

In many embodiments, the antihistamine comprises an H3-receptor antagonist.

In many embodiments, the H3-receptor antagonist comprises one or more of A-349,821, ABT-239, Ciproxifan, Clobenpropit, or Thioperamide.

In many embodiments, the antihistamine comprises an H4-receptor antagonist.

In many embodiments, the H4-receptor antagonist comprises one or more of Thioperamide, JNJ 7777120, or VUF-6002.

In another aspect, embodiments provide an apparatus to treat an eye having a sclera and a vitreous humor. A therapeutic device is configured to couple to the sclera. The therapeutic device comprises a first container to hold a first therapeutic agent, and the first container has a second therapeutic agent with in the container to release therapeutic amounts of the second therapeutic agent into the vitreous humor for a second extended time when the therapeutic device is inserted into the eye.

In another aspect, embodiments provide an apparatus to treat an eye having a sclera and a vitreous humor. A therapeutic device is configured to couple to the sclera. The therapeutic device comprises a first container to hold a first therapeutic agent and a second container to hold a second therapeutic agent. The first container is configured to release first therapeutic amounts of the first therapeutic agent into the vitreous humor for a first extended time, and the second container is configured to release second therapeutic amounts of the second therapeutic agent into the vitreous humor for a second extended time.

In another aspect, an apparatus to treat an eye having a sclera and a vitreous humor comprises a first therapeutic device and a second therapeutic device. The first therapeutic device comprises a first container configured to couple to the sclera and hold a first therapeutic agent. The first container is configured to release first therapeutic amounts of the first therapeutic agent into the vitreous humor for a first extended time. The second therapeutic device comprises a second container configured to couple to the sclera and hold a second therapeutic agent. The second container configured to release second therapeutic amounts of the second therapeutic agent into the vitreous humor for a second extended time.

In many embodiments, the first therapeutic device and the second therapeutic device each comprises a portion to couple to the sclera having an oval cross section sized to fit an incision extending along the pars plana.

In many embodiments, the first therapeutic agent comprises a VEGF inhibitor and the second therapeutic agent comprises a COX inhibitor.

In many embodiments, the therapeutic device comprises a first chamber to receive an injection of the first therapeutic agent, and the first chamber is coupled to a first porous structure to contain the first therapeutic agent and release therapeutic amounts of the first therapeutic agent with a first release rate profile for the first extended time.

In many embodiments, the COX inhibitor comprises a substantially water insoluble COX inhibitor to release the therapeutic agent with a second release rate profile for the second extended time.

In many embodiments, further comprising a second chamber to the water insoluble COX inhibitor and a second porous structure coupled to the second chamber to release the water insoluble COX inhibitor through the second porous structure.

In many embodiments, the first chamber is coupled to the second chamber with the first porous structure, the first porous structure having a first release rate index, the second porous structure having a second release rate index, wherein the first release rate index is smaller than the second release rate index, such that the release rate profile of the first therapeutic agent is determined substantially based on the first release rate index and the release rate profile of the second therapeutic agent is determined substantially based on the second release rate index.

In another aspect, a therapeutic device to treat a patient, the device comprises means for releasing therapeutic amounts of a therapeutic agent for an extended period.

In a another aspect, a sustained drug delivery formulation comprising a first and second therapeutic agent wherein the first and second therapeutic agent is contained/disposed in a reservoir in at least one apparatus/therapeutic device of any one of claims 42 to 51, and at least one of the first and second therapeutic agent has a half-life within the reservoir when implanted, the half life within the reservoir substantially greater than a corresponding half-life of the at least one of the first and second therapeutic agent when injected directly into the vitreous of an eye.

In many embodiments, the device can be configured by selection of the reservoir volume and a porous structure with an appropriate rate release index to achieve the desired effective half-life.

In many embodiments, the rate release index is from about 0.01 to about 5.

In many embodiments, the first therapeutic agent is a VEGF-inhibitor and the second therapeutic agent is an inflammatory response inhibitor.

In many embodiments, the VEGF inhibitor is selected from the group consisting of Ranibizumab, Bevacizumab and Aflibercept™.

In many embodiments, the VEGF inhibitor is Ranibizumab.

In many embodiments, the inflammatory response inhibitor is selected from the group consisting of Piroxicam, Meloxicam, Tenoxicam, Droxicam, Lornoxicam, Isoxicam, Mefenamic acid, Meclofenamic acid, Flufenamic acid, and Tolfenamic acid.

In many embodiments, the inflammatory response inhibitor is selected from the group consisting of a cyclooxygenase (COX) inhibitor, a lipoxygenase (LOX) inhibitor and a tumor necrosis factor (TNF).

In many embodiments, the cox inhibitor is selected from the group consisting of celecoxib, valdecoxib, rofecoxib, parecoxib, lumiracoxib, etoricoxib, aspirin, ibuprofen, naproxen, fenoprofen, ketoprofen, flurbiprofen, oxaprozin, indomethacin, sulindac, etodolac, diclofenac, nabumetone, meloxicam, ketorolac, flurbiprofen, bromfenac, nepafenac, and amfenac.

In many embodiments, the lox inhibitor is selected from the group consisting of azelastine and zileuton.

In many embodiments, the TNF is selected from the group consisting of bupropion, pentoxifylline, infliximab, adalimumab, and etanercept.

In many embodiments, the concentration of the first therapeutic agent is greater than about 40 mg/ml.

In many embodiments, the concentration of the first therapeutic agent is from about 50 mg/ml to about 300 mg/ml.

In many embodiments, the concentration of the first therapeutic agent is about 100 mg/ml to about 250 mg/ml.

In many embodiments, the concentration of the first therapeutic agent is about 150 mg/ml to about 200 mg/ml.

In many embodiments, the amount of the first therapeutic agent is greater than about 50 mg.

In many embodiments, at least one of the first or second therapeutic agent is administered in a sub-therapeutic dosage.

In many embodiments, at least one of the first or second therapeutic agent is contained/disposed in a micelle.

In many embodiments, at least one of the first and second therapeutic agent is stabilized by adsorption onto solid substrate or macromolecule that is capable of being flushed from the eye.

In many embodiments, the first and second therapeutic agents are contained/disposed in one apparatus/therapeutic device.

In many embodiments, the first therapeutic agent is contained/disposed in a first apparatus/therapeutic device and the second therapeutic agent is contained/disposed in a second apparatus/therapeutic device.

In many embodiments, the first and second therapeutic agents are administered simultaneously.

In many embodiments, the first and second therapeutic agents are administered sequentially.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an eye suitable for incorporation of the therapeutic device, in accordance with embodiments of the present invention;

FIG. 1A-1 shows a therapeutic device implanted at least partially within the sclera of the eye as in FIG. 1;

FIG. 1A-1-1 and 1A-1-2 show a therapeutic device implanted under the conjunctiva and extending through the sclera to release a therapeutic agent into vitreous humor of the eye so as to treat the retina of the, in accordance with embodiments of the present invention;

FIG. 1A-2 shows structures of a therapeutic device configured for placement in an eye as in FIGS. 1A-1 and 1A-1-1, according to embodiments of the present invention;

FIG. 1A-2-1 shows a therapeutic device loaded into an insertion cannula, in which the device comprises an elongate narrow shape for insertion into the sclera, and in which the device is configured to expand to a second elongate wide shape for retention at least partially in the sclera;

FIG. 1A-2-2 shows a therapeutic device comprising a reservoir suitable for loading in a cannula;

FIG. 1B shows a therapeutic device configured for placement in an eye as in FIG. 1A-1 and 1A-1-1, in accordance with embodiments of the present invention;

FIG. 1C shows a therapeutic device configured for placement in an eye as in FIG. 1A-1 and 1A-1-1, in accordance with embodiments of the present invention;

FIG. 1C-A shows at least one exit port, according to embodiments of the present invention;

FIG. 1C-1 shows a method of removing a binding material, according to embodiments of the present invention;

FIG. 1C-2 and inserting the therapeutic agent with a second insert having the TA bound thereon;

FIG. 1C-3 shows syringe being filled with a commercially available formulation of therapeutic agent for injection into the therapeutic device, in accordance with embodiments;

FIG. 2 shows a first therapeutic agent contained in a first injector and a second therapeutic agent contained in a second injector to treat the patient;

FIG. 3 shows a first therapeutic agent contained in a first injector injected directly into the vitreous humor of the eye and a second therapeutic agent contained in a second injector injected into therapeutic device so as to treat the patient;

FIG. 4 shows a plurality of therapeutic devices implanted into the eye to deliver therapeutic amounts of first therapeutic agent and second therapeutic agent;

FIG. 5 shows a therapeutic device having a plurality of parallel reservoirs comprising a first reservoir and a second reservoir;

FIG. 6A shows a therapeutic device having a plurality of reservoirs configured in series comprising a first reservoir and a second reservoir;

FIG. 6B shows a rigid porous structure configured for sustained release with a device as in FIG. 6A;

FIG. 6B-1 shows interconnecting channels extending from a first side to a second side of the porous structure as in FIG. 6B;

FIG. 6B-2 shows a plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side to a second side of the porous structure as in FIGS. 6B and 6B1;

FIG. 6B-3 shows blockage of the openings with a covering and the plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side to a second side of the porous structure as in FIGS. 6B and 6B-1;

FIG. 6B-4 shows blockage of the openings with particles and the plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side to a second side of the porous structure as in FIGS. 6B and 6B-1;

FIG. 6B-5 shows an effective cross-sectional size and area corresponding to the plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side to a second side of the porous structure as in FIGS. 6B and 6B-1;

FIG. 6C shows a rigid porous structure as in FIG. 6B incorporated into a scleral tack;

FIG. 6D, shows a rigid porous structure as in FIG. 6B coupled with a reservoir for sustained release;

FIG. 6E shows a rigid porous structure as in FIG. 6B comprising a hollow body or tube for sustained release;

FIG. 6F shows a rigid porous structure as in FIG. 6B comprising a non-linear helical structure for sustained release;

FIG. 6G shows porous nanostructures, in accordance with embodiments;

FIG. 7 shows a therapeutic device coupled to an injector that removes material from the device and injects therapeutic agent into the device, according to embodiments;

FIG. 7A shows a therapeutic device having a reservoir tuned to receive an injection of a first amount of first therapeutic agent and a second amount of second therapeutic agent;

FIG. 7A-1 shows a therapeutic device coupled to an injector needle comprising a stop that positions the distal end of the needle near the proximal end of the device to flush the reservoir with ejection of liquid formulation through the porous fit structure, in accordance with embodiments;

FIG. 7A-2 shows a therapeutic device comprising a penetrable barrier coupled to an injector to inject and remove material from the device such that the liquid in the reservoir is exchanged with the injected formulation, in accordance with embodiments;

FIG. 7B-1 shows a side cross-sectional view of therapeutic device comprising a retention structure having a cross-section sized to fit in an elongate incision;

FIG. 7B-2 shows an isometric view of the therapeutic device as in FIG. 7B-1;

FIG. 7B-3 shows a top view of the therapeutic device as in FIG. 7B-1;

FIG. 7B-4 shows a side cross sectional view along the short side of the retention structure of the therapeutic device as in FIG. 7B-1;

FIG. 7B-5 shows a bottom view of the therapeutic device as in FIG. 7B-1 implanted in the sclera;

FIG. 7B-5A shows a cutting tool comprising a blade having a width corresponding to perimeter of the barrier and the perimeter of the narrow portion;

FIGS. 8A and 8A1 show a side cross sectional view and a top view, respectively, of the therapeutic device for placement substantially between the conjunctiva and the sclera;

FIG. 8A2 shows the therapeutic device implanted with the reservoir between the conjunctiva and the sclera, such that elongate structure extends through the sclera to couple the reservoir chamber to the vitreous humor;

FIG. 9 shows the porous structure of therapeutic device located in channel near the opening to the chamber of the container;

FIG. 10 shows the porous structure located within the chamber of container and coupled to the first opening of the elongate structure so as to provide the release rate profile;

FIG. 11 shows a plurality of injection ports spaced apart so as to inject and exchange the liquid of chamber of the container and inject the therapeutic agent into the reservoir chamber of the container; and

FIG. 12 shows the elongate structure coupled to the container away from the center of the container and near and located near an end of the container;

FIG. 13 shows the cumulative release of BSA protein through a sintered porous titanium cylinder;

FIG. 13-1 shows the measured cumulative release of BSA of FIG. 13 measured to 180 days;

FIG. 14 shows the cumulative release of BSA protein through a masked sintered porous titanium cylinder at Condition 1, in accordance with experimental embodiments;

FIG. 15 shows cumulative release of BSA protein through a masked sintered porous titanium cylinder at Condition 2, in accordance with experimental embodiments;

FIG. 16 shows cumulative release of BSA protein through a masked sintered porous titanium cylinder at Condition 3, in accordance with experimental embodiments;

FIG. 17 shows cumulative release of BSA through 0.1 media grade sintered porous stainless steel cylinder;

FIG. 18A shows cumulative release of BSA through 0.2 media grade sintered porous stainless steel cylinder;

FIG. 18B shows cumulative release of BSA through 0.2 media grade sintered porous stainless steel cylinder for 180 days;

FIG. 19A compares calculated Lucentis™ pharmacokinetics profiles to the pharmacokinetics profiles predicted for the device in Example 8;

FIG. 19B shows determined concentrations of ranibizumab in the vitreous humor for a a first 50 uL Lucentis™ injection into a 25 uL reservoir of the device and a second 50 uL injection at 90 days, in accordance with embodiments;

FIG. 19C shows determined concentrations of ranibizumab in the vitreous humor for a first 50 uL Lucentis™ injection into a 32 uL reservoir of the device and a second 50 uL injection at 90 days, in accordance with embodiments;

FIG. 19D shows determined concentrations of ranibizumab in the vitreous humor for a first 50 uL Lucentis™ injection into a 50 uL reservoir of the device and a second 50 uL injection at 90 days, in accordance with embodiments;

FIG. 19E shows determined concentrations of ranibizumab in the vitreous humor for a first 50 uL Lucentis™ injection into a 50 uL reservoir of the device and a second 50 uL injection at 130 days, in accordance with embodiments;

FIG. 19F shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 50 uL device having a release rate index of 0.05, in accordance with embodiments;

FIG. 19G shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 75 uL device having a release rate index of 0.05, in accordance with embodiments;

FIG. 19H shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 100 uL device having a release rate index of 0.05, in accordance with embodiments;

FIG. 19I shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL device having a release rate index of 0.05, in accordance with embodiments;

FIG. 19J shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 150 uL device having a release rate index of 0.05, in accordance with embodiments;

FIG. 19K shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 100 uL device having a release rate index of 0.1, in accordance with embodiments;

FIG. 19L shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.105, in accordance with embodiments;

FIG. 19M shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.095, in accordance with embodiments;

FIG. 19N shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.085, in accordance with embodiments;

FIG. 19O shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.075, in accordance with embodiments;

FIG. 19P shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.065, in accordance with embodiments;

FIG. 19Q shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL concentrated Lucentis™ (40 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about nine days, in accordance with embodiments;

FIG. 19R shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL concentrated Lucentis™ (40 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about five days, in accordance with embodiments;

FIG. 19S shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL standard Lucentis™ (10 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about nine days, in accordance with embodiments;

FIG. 19T shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL standard Lucentis™ (10 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about five days, in accordance with embodiments;

FIG. 20 shows a calculated time release profile of a therapeutic agent suspension in a reservoir, in accordance with embodiments.

FIG. 21 shows cumulative release for Avastin™ with therapeutic devices comprising substantially similar porous frit structures and a 16 uL reservoir and a 33 uL reservoir;

FIG. 22A shows cumulative release for Avastin™ with porous fit structures having a thickness of 0.049″;

FIG. 22B-1 shows cumulative release for Avastin™ with porous fit structures having a thickness of 0.029″;

FIG. 22B-2 shows rate of release for Avastin™ with porous frit structures having a thickness of 0.029″ as in FIG. 22B-1;

FIG. 23A shows cumulative release for Avastin™ with a reservoir volume of 20 uL;

FIG. 23A-1 shows cumulative release to about 90 days for Avastin™ with a reservoir volume of 20 uL as in FIG. 23A;

FIG. 23B shows rate of release as in FIG. 23A;

FIG. 23B-1 shows rate of release as in FIG. 23A-1;

FIG. 24A shows cumulative release for Avastin™ with a 0.1 media grade porous fit structure;

FIG. 24A-1 shows cumulative release to about 90 days release for Avastin™ with a 0.1 media grade porous frit structure as in FIG. 24A;

FIG. 24B shows rates of release of the devices as in FIG. 24A;

FIG. 24B-1 shows rates of release of the devices as in FIG. 24A-1;

FIG. 25A shows cumulative release for fluorescein through a 0.2 media grade porous frit structure;

FIG. 25A-1 shows cumulative release to about 90 days for fluorescein through a 0.2 media grade porous frit structure as in FIG. 25A;

FIG. 25B shows rates of release of the devices as in FIG. 25A;

FIG. 25B-1 shows rates of release of the devices as in FIG. 25A-1;

FIG. 25C shows cumulative release to about thirty days for Lucentis™ through a 0.2 media grade porous fit structure having a diameter of 0.038 in and a length (thickness) of 0.029 in.;

FIG. 25D shows rates of release of the devices as in FIG. 25C;

FIG. 25E shows cumulative release to about thirty days for Lucentis™ for 30 uL devices having a RRI's from about 0.015 to about 0.090;

FIG. 25F shows rates of release of the devices as in FIG. 25E;

FIGS. 26A and 26B show scanning electron microscope images from fractured edges of porous frit structures so as to show the structure of the porous structure to release the therapeutic agent, in accordance with embodiments;

FIGS. 27A and 27B show scanning electron microscope images from surfaces of porous frit structures, in accordance with embodiments;

FIG. 28 shows a pressure decay test and test apparatus for use with a porous structure so as to identify porous frit structures suitable for use with therapeutic devices in accordance with embodiments described herein; and

FIG. 29 shows a pressure flow test and test apparatus suitable for use with a porous structure so as to identify porous frit structures suitable for use with therapeutic devices in accordance with embodiments described herein.

DETAILED DESCRIPTION OF THE INVENTION

Although specific reference is made to the delivery of macromolecules comprising antibodies or antibody fragments to the posterior segment of the eye, embodiments of the present invention can be used to deliver many therapeutic agents to many tissues of the body. For example, embodiments of the present invention can be used to deliver therapeutic agent for an extended period to one or more of the following tissues: intravascular, intra articular, intrathecal, pericardial, intraluminal and gut.

The therapeutic agents and devices as described herein can be used to deliver combinations of therapeutic agents for an extended time. The combined therapeutic agents can be used to treat many disease of the eye, for example age related macular degeneration (hereinafter “AMD”).

The embodiments as described herein may incorporate one or more components of the methods and apparatus described in U.S. application Ser. No. 12/696,678, filed Jan. 29, 2010, entitled “Posterior Segment Drug Delivery”, published as U.S. Pat. App. Pub. No. 2010/0255061 (attorney docket not. 026322-003750US); PCT/US2010/022631, published as WO2010/088548, entitled “Posterior Segment Drug Delivery”; and priority U.S. Provisional Pat. App. Ser. No. 61/371,168, filed 5 Aug. 2010, the full disclosures of which are incorporated by reference.

Embodiments of the present invention provide sustained release of a therapeutic agent to the posterior segment of the eye or the anterior segment of the eye, or combinations thereof. Therapeutic amounts of a therapeutic agent can be released into the vitreous humor of the eye, such that the therapeutic agent can be transported by at least one of diffusion or convection to the retina or other ocular tissue, such as the choroid or ciliary body, for therapeutic effect.

As used herein the release rate index encompasses (PA/FL) where P comprises the porosity, A comprises an effective area, F comprises a curve fit parameter corresponding to an effective length and L comprises a length or thickness of the porous structure. The units of the release rate index (RRI) comprise units of mm unless indicated otherwise and can be determined by a person of ordinary skill in the art in accordance with the teachings described hereon.

As used herein, sustained release encompasses release of therapeutic amounts of an active ingredient of a therapeutic agent for an extended period of time. The sustained release may encompass first order release of the active ingredient, zero order release of the active ingredient, or other kinetics of release such as intermediate to zero order and first order, or combinations thereof.

As used herein a therapeutic agent referred to with a trade name encompasses one or more of the formulation of the therapeutic agent commercially available under the tradename, the active ingredient of the commercially available formulation, the generic name of the active ingredient, or the molecule comprising the active ingredient.

As used herein, similar numerals indicate similar structures and/or similar steps.

As used herein, the terms first and second identify components of combinations and can be in any order, for example reversed, or simultaneous, in accordance with the teachings and embodiments described herein.

As used herein, a therapeutic device implanted in the eye encompasses at least a portion of the therapeutic device placed under the conjunctiva of the eye.

The therapeutic agent may be contained within a chamber of a container, for example within a reservoir comprising the container and chamber. The therapeutic agent may comprise a formulation such as solution of therapeutic agent, a suspension of a therapeutic agent or a dispersion of a therapeutic agent, for example. Examples of therapeutic agents suitable for use in accordance with embodiments of the therapeutic device are described herein, for example with reference to Table 1A below and elsewhere.

The therapeutic agent may comprise a macromolecule, for example an antibody or antibody fragment. The therapeutic macromolecule may comprise a VEGF inhibitor, for example commercially available Lucentis™. The VEGF (Vascular Endothelial Growth Factor) inhibitor can cause regression of the abnormal blood vessels and improvement of vision when released into the vitreous humor of the eye. Examples of VEGF inhibitors include Lucentis™, Avastin™, Macugen™, and VEGF Trap.

The therapeutic agent may comprise small molecules such as of a corticosteroid and analogues thereof. For example, the therapeutic corticosteroid may comprise one or more of triamcinolone, triamcinolone acetonide, dexamethasone, dexamethasone acetate, fluocinolone, fluocinolone acetate, or analogues thereof. Alternatively or in combination, the small molecules of therapeutic agent may comprise a tyrosine kinase inhibitor comprising one or more of axitinib, bosutinib, cediranib, dasatinib, erlotinib, gefitinib, imatinib, lapatinib, lestaurtinib, nilotinib, semaxanib, sunitinib, toceranib, vandetanib, or vatalanib, for example.

The therapeutic agent may comprise an anti-VEGF therapeutic agent. Anti-VEGF therapies and agents can be used in the treatment of certain cancers and in age-related macular degeneration. Examples of anti-VEGF therapeutic agents suitable for use in accordance with the embodiments described herein include one or more of monoclonal antibodies such as bevacizumab (Avastin™) or antibody derivatives such as ranibizumab (Lucentis™), or small molecules that inhibit the tyrosine kinases stimulated by VEGF such as lapatinib (Tykerb™), sunitinib (Sutent™), sorafenib (Nexavar™), axitinib, or pazopanib.

The therapeutic agent may comprise a therapeutic agent suitable for treatment of dry AMD such as one or more of Sirolimus™ (Rapamycin), Copaxone™ (Glatiramer Acetate), Othera™, Complement C5aR blocker, Ciliary Neurotrophic Factor, Fenretinide or Rheopheresis.

The therapeutic agent may comprise a therapeutic agent suitable for treatment of wet AMD such as one or more of REDD14NP (Quark), Sirolimus™ (Rapamycin), ATG003; Regeneron™ (VEGF Trap) or complement inhibitor (POT-4).

The therapeutic agent may comprise a kinase inhibitor such as one or more of bevacizumab (monoclonal antibody), BIBW 2992 (small molecule targeting EGFR/Erb2), cetuximab (monoclonal antibody), imatinib (small molecule), trastuzumab (monoclonal antibody), gefitinib (small molecule), ranibizumab (monoclonal antibody), pegaptanib (small molecule), sorafenib (small molecule), dasatinib (small molecule), sunitinib (small molecule), erlotinib (small molecule), nilotinib (small molecule), lapatinib (small molecule), panitumumab (monoclonal antibody), vandetanib (small molecule) or E7080 (targeting VEGFR2/VEGFR2, small molecule commercially available from Esai, Co.)

The amount of therapeutic agent within the therapeutic device may comprise from about 0.01 mg to about 1 mg, for example Lucentis™, so as to provide therapeutic amounts of the therapeutic agent for the extended time, for example at least 30 days. The extended time may comprise at least 90 days or more, for example at least 180 days or for example at least 1 year, at least 2 years or at least 3 years or more. The target threshold therapeutic concentration of a therapeutic agent such as Lucentis™ in the vitreous may comprise at least a therapeutic concentration of 0.1 ug/mL. For example the target threshold concentration may comprise from about 0.1 ug/mL to about 5 ug/mL for the extended time, where the upper value is based upon calculations shown in Example 9 using published data. The target threshold concentration is drug dependent and thus may vary for other therapeutic agents.

The delivery profile may be configured in many ways to obtain a therapeutic benefit from the sustained release device. For example, an amount of the therapeutic agent may be inserted into the container at monthly intervals so as to ensure that the concentration of therapeutic device is above a safety protocol or an efficacy protocol for the therapeutic agent, for example with monthly or less frequent injections into the container. The sustained release can result in an improved delivery profile and may result in improved results. For example, the concentration of therapeutic agent may remain consistently above a threshold amount, for example 0.1 ug/mL, for the extended time.

The insertion method may comprise inserting a dose into the container of the therapeutic device. For example, a single injection of Lucentis™ may be injected into the therapeutic device.

The duration of sustained delivery of the therapeutic agent may extend for twelve weeks or more, for example four to six months from a single insertion of therapeutic agent into the device when the device is inserted into the eye of the patient.

The therapeutic agent may be delivered in many ways so as to provide a sustained release for the extended time. For example, the therapeutic device may comprise a therapeutic agent and a binding agent. The binding agent may comprise small particles configured to couple releasably or reversibly to the therapeutic agent, such that the therapeutic agent is released for the extended time after injection into the vitreous humor. The particles can be sized such that the particles remain in the vitreous humor of the eye for the extended time.

The therapeutic agent may be delivered with a device implanted in the eye. For example, the drug delivery device can be implanted at least partially within the sclera of the eye, so as to couple the drug delivery device to the sclera of the eye for the extended period of time. The therapeutic device may comprise a drug and a binding agent. The drug and binding agent can be configured to provide the sustained release for the extended time. A membrane or other diffusion barrier or mechanism may be a component of the therapeutic device to release the drug for the extended time.

The lifetime of the therapeutic device and number of injections can be optimized for patient treatment. For example, the device may remain in place for a lifetime of 30 years, for example with AMD patients from about 10 to 15 years. For example, the device may be configured for an implantation duration of at least two years, with 8 injections (once every three months) for sustained release of the therapeutic agent over the two year duration. The device may be configured for implantation of at least 10 years with 40 injections (once every three months) for sustained release of the therapeutic agent.

The therapeutic device can be refilled in many ways. For example, the therapeutic agent can be refilled into the device in the physician's office.

The therapeutic device may comprise many configurations and physical attributes, for example the physical characteristics of the therapeutic device may comprise at least one of a drug delivery device with a suture, positioning and sizing such that vision is not impaired, and biocompatible material. The device may comprise a reservoir capacity from about 0.005 cc to about 0.2 cc, for example from about 0.01 cc to about 0.1 cc, and a device volume of no more than about 2 cc. A vitrectomy may be performed for device volumes larger than 0.1 cc. The length of the device may not interfere with the patient's vision and can be dependent on the shape of the device, as well as the location of the implanted device with respect to the eye. The length of the device may also depend on the angle in which the device is inserted. For example, a length of the device may comprise from about 4 to 6 mm. Since the diameter of the eye is about 24 mm, a device extending no more than about 6 mm from the sclera into the vitreous may have a minimal effect on patient vision.

Embodiments may comprise many combinations of implanted drug delivery devices. The therapeutic device may comprise a drug and binding agent. The device may also comprise at least one of a membrane, an opening, a diffusion barrier, a diffusion mechanism so as to release therapeutic amounts of therapeutic agent for the extended time.

FIG. 1 shows an eye 10 suitable for incorporation of the therapeutic device. The eye has a cornea 12 and a lens 22 configured to form an image on the retina 26. The cornea can extend to a limbus 14 of the eye, and the limbus can connect to a sclera 24 of the eye. A conjunctiva 16 of the eye can be disposed over the sclera. The lens can accommodate to focus on an object seen by the patient. The eye has an iris 18 that may expand and contract in response to light. The eye also comprises a choroid 28 disposed the between the sclera 24 and the retina 26. The retina comprises the macula 32. The eye comprises a pars plana 25, which comprises an example of a region of the eye suitable for placement and retention, for example anchoring, of the therapeutic device 100 as described herein. The pars plana region may comprise sclera and conjunctiva disposed between the retina and cornea. The therapeutic device can be positioned so as to extend from the pars plana region into the vitreous humor 30 to release the therapeutic agent. The therapeutic agent can be released into the vitreous humor 30, such that the therapeutic agent arrives at the retina and choroids for therapeutic effect on the macula. The vitreous humor of the eye comprises a liquid disposed between the lens and the retina. The vitreous humor may comprise convection currents to deliver the therapeutic agent to the macula.

FIG. 1A-1 shows a therapeutic device 100 implanted at least partially within the sclera 24 of the eye 10 as in FIG. 1. The therapeutic device may comprise a retention structure, for example a protrusion, to couple the device to the sclera. The therapeutic device may extend through the sclera into vitreous humor 30, such that the therapeutic device can release the therapeutic agent into the vitreous humor.

FIGS. 1A-1-1 and 1A-1-2 shows a therapeutic device 100 implanted under the conjunctiva 16 and extending through the sclera 24 to release a therapeutic agent 110 into vitreous humor 30 of the eye 10 so as to treat the retina of the eye. The therapeutic device 100 may comprise a retention structure 120 such as a smooth protrusion configured for placement along the sclera and under the conjunctiva, such that the conjunctiva can cover the therapeutic device and protect the therapeutic device 100. When the therapeutic agent 110 is inserted into the device 100, the conjunctiva may be lifted away, incised, or punctured with a needle to access the therapeutic device. The eye may comprise an insertion of the tendon 27 of the superior rectus muscle to couple the sclera of the eye to the superior rectus muscle. The device 100 may be positioned in many locations of the pars plana region, for example away from tendon 27 and one or more of posterior to the tendon, posterior to the tendon, under the tendon, or with nasal or temporal placement of the therapeutic device.

While the implant can be positioned in the eye in many ways, work in relation to embodiments suggests that placement in the pars plana region can release therapeutic agent into the vitreous to treat the retina, for example therapeutic agent comprising an active ingredient composed of large molecules.

Therapeutic agents 110 suitable for use with device 100 includes many therapeutic agents, for example as listed in Table 1A, herein below. The therapeutic agent 110 of device 100 may comprise one or more of an active ingredient of the therapeutic agent, a formulation of the therapeutic agent, a commercially available formulation of the therapeutic agent, a physician prepared formulation of therapeutic agent, a pharmacist prepared formulation of the therapeutic agent, or a commercially available formulation of therapeutic agent having an excipient. The therapeutic agent may be referred to with generic name or a trade name, for example as shown in Table 1A.

The therapeutic device 100 can be implanted in the eye to treat the eye for as long as is helpful and beneficial to the patient. For example the device can be implanted for at least about 5 years, such as permanently for the life of the patient. Alternatively or in combination, the device can be removed when no longer helpful or beneficial for treatment of the patient.

FIG. 1A-2 shows structures of therapeutic device 100 configured for placement in an eye as in FIGS. 1A-1, 1A-1-1 and 1A-1-2. The device may comprise retention structure 120 to couple the device 100 to the sclera, for example a protrusion disposed on a proximal end of the device. The device 100 may comprise a container 130 affixed to the retention structure 120. An active ingredient, for example therapeutic agent 110, can be contained within a reservoir 140, for example a chamber 132 defined by a container 130 of the device. The container 130 may comprise a porous structure 150 comprising a porous material 152, for example a porous glass frit 154, and a barrier 160 to inhibit release of the therapeutic agent, for example non-permeable membrane 162. The non-permeable membrane 162 may comprise a substantially non-permeable material 164. The non-permeable membrane 162 may comprise an opening 166 sized to release therapeutic amounts of the therapeutic agent 110 for the extended time. The porous structure 150 may comprise a thickness 150T and pore sizes configured in conjunction with the opening 166 so as to release therapeutic amounts of the therapeutic agent for the extended time. The container 130 may comprise reservoir 140 having a chamber with a volume 142 sized to contain a therapeutic quantity of the therapeutic agent 110 for release over the extended time. The device may comprise a needle stop 170. Proteins in the vitreous humor may enter the device and compete for adsorption sites on the porous structure and thereby may contribute to the release of therapeutic agent. The therapeutic agent 110 contained in the reservoir 140 can equilibrate with proteins in the vitreous humor, such that the system is driven towards equilibrium and the therapeutic agent 110 is released in therapeutic amounts.

The non-permeable membrane 162, the porous material 152, the reservoir 140, and the retention structure 120, may comprise many configurations to deliver the therapeutic agent 110. The non-permeable membrane 162 may comprise an annular tube joined by a disc having at least one opening formed thereon to release the therapeutic agent. The porous material 152 may comprise an annular porous glass fit 154 and a circular end disposed thereon. The reservoir 140 may be shape-changing for ease of insertion, i.e. it may assume a thin elongated shape during insertion through the sclera and then assume an extended, ballooned shape, once it is filled with therapeutic agent.

The porous structure 150 can be configured in many ways to release the therapeutic agent in accordance with an intended release profile. For example, the porous structure may comprise a porous structure having a plurality of openings on a first side facing the reservoir and a plurality of openings on a second side facing the vitreous humor, with a plurality of interconnecting channels disposed there between so as to couple the openings of the first side with the openings of the second side, for example a sintered rigid material. The porous structure 150 may comprise one or more of a permeable membrane, a semi-permeable membrane, a material having at least one hole disposed therein, nano-channels, nano-channels etched in a rigid material, laser etched nano-channels, a capillary channel, a plurality of capillary channels, one or more tortuous channels, tortuous microchannels, sintered nano-particles, an open cell foam or a hydrogel such as an open cell hydrogel.

FIG. 1A-2-1 shows therapeutic device 100 loaded into an insertion cannula 210 of an insertion apparatus 200, in which the device 100 comprises an elongate narrow shape for insertion into the sclera, and in which the device is configured to expand to a second elongate wide shape for retention at least partially in the sclera;

FIG. 1A-2-2 shows a therapeutic device 100 comprising reservoir 140 suitable for loading in a cannula, in which the reservoir 140 comprises an expanded configuration.

FIG. 1B shows therapeutic device 100 configured for placement in an eye as in FIG. 1A-1 and 1A-1-1. The device comprises retention structure 120 to couple to the sclera, for example flush with the sclera, and the barrier 160 comprises a tube 168. An active ingredient 112 comprising the therapeutic agent 110 is contained within tube 168 comprising non-permeable material 164. A porous material 152 is disposed at the distal end of the tube 168 to provide a sustained release of the therapeutic agent at therapeutic concentrations for the extended period. The non-permeable material 164 may extend distally around the porous material 152 so as to define an opening to couple the porous material 152 to the vitreous humor when the device is inserted into the eye.

The tube 168 and retention structure 120 may be configured to receive a glass rod, which is surface treated, and the glass rod can be injected with therapeutic agent. When the therapeutic agent has finished elution for the extended time, the rod can be replaced with a new rod.

The device 100 may comprise therapeutic agent and a carrier, for example a binding medium comprising a binding agent to deliver the therapeutic agent. The therapeutic agent can be surrounded with a column comprising a solid support that is eroded away.

FIG. 1C shows a therapeutic device configured for placement in an eye as in FIG. 1A-1 and 1A-1-1. A binding medium 192 comprising a binding agent 190 such as glass wool may be loaded with therapeutic agent 110 prior to injection into the device through an access port 180. The device 100 may comprise binding, leak, and barrier functions to deliver the therapeutic agent for the extended time. The binding medium 192 and therapeutic agent 110 can be aspirated to replace the binding medium and therapeutic agent. The binding medium can be at least one of flushed or replaced when at least majority of the therapeutic agent has been released, such that additional therapeutic agent can be delivered from a second, injected binding medium comprising therapeutic agent. A membrane 195 can be disposed over the periphery of the therapeutic device 100. The membrane 195 may comprise methylcellulose, regenerated cellulose, cellulose acetate, nylon, polycarbonate, poly(tetrafluoroethylene) (PTFE), polyethersulfone, and polyvinylidene difluoride (PVDF). The therapeutic device may comprise barrier 160 shaped such that opening 166 comprises an exit port. The therapeutic agent may be released through at least one of a diffusion mechanism or convection mechanism. The number, size, and configuration of exit ports may determine the release rate of the therapeutic agent. The exit port may comprise a convection port, for example at least one of an osmotically driven convection port or a spring driven convection port. The exit port may also comprise a tubular path to which the therapeutic agent may temporarily attach, and then be released under certain physical or chemical conditions.

FIG. 1C-A shows at least one exit port 167, the exit port can be disposed on the device 100 to allow liquid to flow from inside the device outward, for example when fluid is injected into an injection port 182 of the device or when an insert such as a glass frit is inserted into the device. The therapeutic device may comprise an access port 180 for injection and/or removal, for example a septum. Additionally or in the alternative, when the therapeutic device is refilled, the contents of the device may be flushed into the vitreous of the eye.

FIG. 1C-1 shows a method of removing a binding agent 194. A needle 189 coupled to a syringe 188 of an injector 187 can be inserted into an access port 180 of the therapeutic device 100. The binding agent 194 can be aspirated with a needle.

FIG. 1C-2 shows a method of inserting the therapeutic agent 110 with a second binding agent 190 having the therapeutic agent 110 bound thereon. The therapeutic agent can be injected into a container 130 of the device for sustained release over the extended time.

FIG. 1C-3 shows syringe being filled with a formulation of therapeutic agent for injection into the therapeutic device. The needle 189 coupled to syringe 188 of injector 187 can be used to draw therapeutic agent 110 from a container 110C. The container 110C may comprise a commercially available container, such as a bottle with a septum, a single dose container, or a container suitable for mixing formulations. A quantity 110V of therapeutic agent 110 can be drawn into injector 187 for injection into the therapeutic device 100 positioned within the eye. The quantity 110V may comprise a predetermined quantity, for example based on the volume of the container of the therapeutic device 110 and an intended injection into the vitreous humor. The example the quantity 110V may exceed the volume of the container so as to inject a first portion of quantity 110V into the vitreous humor through the therapeutic device and to contain a second portion of quantity 110V within the container of the therapeutic device 110. Container 110C may comprise a formulation 110F of the therapeutic agent 110. The formulation 110F may comprise a commercially available formulations of therapeutic agent, for example therapeutic agents as described herein and with reference to Table 1A. Non-limiting examples of commercially available formulations that may be suitable for use in accordance with the embodiments described herein include Lucentis™ and Triamcinolone, for example. The formulation 110F may be a concentrated or diluted formulation of a commercially available therapeutic agent, for example Avastin™. The osmolarity and tonicity of the vitreous humor can be within a range from about 290 to about 320. For example, a commercially available formulation of Avastin™ may be diluted so as to comprise a formulation having an osmolarity and tonicity substantially similar to the osmolarity and tonicity of the vitreous humor, for example within a range from about 280 to about 340, for example about 300 mOsm. While the therapeutic agent 110 may comprise an osmolarity and tonicity substantially similar to the vitreous humor, the therapeutic agent 110 may comprise a hyper osmotic solution relative to the vitreous humor or a hypo osmotic solution relative to the vitreous humor. A person or ordinary skill in the art can conduct experiments based on the teachings described herein so as to determine empirically the formulation and osmolarity of the therapeutic agent to provide release of therapeutic agent for an extended time.

For example, in the United States of America, Lucentis™ (active ingredient ranibizumab) is supplied as a preservative-free, sterile solution in a single-use glass vial designed to deliver 0.05 mL of 10 mg/mL Lucentis™ aqueous solution with 10 mM histidine HCl, 10% α,α-trehalose dihydrate, 0.01% polysorbate 20, at pH 5.5. In Europe, the Lucentis™ formulation can be substantially similar to the formulation of the United States.

For example, the sustained release formulation of Lucentis™ in development by Genentech and/or Novartis, may comprise the therapeutic agent injected in to the device 100. The sustained release formulation may comprise particles comprising active ingredient.

For example, in the United States, Avastin™ (bevacizumab) is approved as an anticancer drug and in clinical trials are ongoing for AMD. For cancer, the commercial solution is a pH 6.2 solution for intravenous infusion. Avastin™ is supplied in 100 mg and 400 mg preservative-free, single-use vials to deliver 4 mL or 16 mL of Avastin™ (25 mg/mL). The 100 mg product is formulated in 240 mg α,α-trehalose dihydrate, 23.2 mg sodium phosphate (monobasic, monohydrate), 4.8 mg sodium phosphate (dibasic, anhydrous), 1.6 mg polysorbate 20, and Water for Injection, USP. The 400 mg product is formulated in 960 mg α,α-trehalose dihydrate, 92.8 mg sodium phosphate (monobasic, monohydrate), 19.2 mg sodium phosphate (dibasic, anhydrous), 6.4 mg polysorbate 20, and Water for Injection, USP. The commercial formulations are diluted in 100 mL of 0.9% sodium chloride before administration and the amount of the commercial formulation used varies by patient and indication. Based on the teachings described herein, a person of ordinary skill in the art can determine formulations of Avastin™ to inject into therapeutic device 100. In Europe, the Avastin™ formulation can be substantially similar to the formulation of the United States.

For example, in the United States, there are 2 forms of Triamcinolone used in injectable solutions, the acetonide and the hexacetonide. The acetamide is approved for intravitreal injections in the U.S. The acetamide is the active ingredient in TRIVARIS (Allergan), 8 mg triamcinolone acetonide in 0.1 mL (8% suspension) in a vehicle containing w/w percents of 2.3% sodium hyaluronate; 0.63% sodium chloride; 0.3% sodium phosphate, dibasic; 0.04% sodium phosphate, monobasic; and water, pH 7.0 to 7.4 for injection. The acetamide is also the active ingredient in Triesence™ (Alcon), a 40 mg/ml suspension.

A person of ordinary skill in the art can determine the osmolarity for the formulations as described herein. The degree of dissociation of the active ingredient in solution can be determined and used to determined differences of osmolarity from the molarity in these formulations. For example, considering at least some of the formulations may be concentrated (or suspensions), the molarity can differ from the osmolarity.

The formulation of therapeutic agent may injected into therapeutic device 100 may comprise many known formulations of therapeutic agents, and the formulation therapeutic agent comprises an osmolatiry suitable for release for an extended time from device 100. Table 1B shows examples of osmolarity (Osm) of saline and some of the commercially formulations of Table 1A.

TABLE 1B Summary of Calculations Description Osm (M) Saline (0.9%) 0.308 Phosphate Buffered Saline (PBS) 0.313 Lucentis ™ 0.289 Avastin ™ 0.182 Triamcinolone Acetonide (Trivaris-Allergan) 0.342 Triamcinolone Acetonide (Triessence-Alcon) Isotonic* Triamcinolone Acetonide (Kenalog-Apothecon) Isotonic* *As described in package insert

The vitreous humor of the eye comprises an osmolarity of about 290 mOsm to about 320 mOsm. Formulations of therapeutic agent having an osmolarity from about 280 mOsm to about 340 mOsm are substantially isotonic and substantially iso-osmotic with respect to the vitreous humor of the eye. Although the formulations listed in Table 1B are substantially iso-osmotic and isotonic with respect to the vitreous of the eye and suitable for injection into the therapeutic device, the formulation of the therapeutic agent injected into the therapeutic device can be hypertonic (hyper-osmotic) or hypotonic (hypo-osmotic) with respect to the tonicity and osmolarity of the vitreous. Work in relation to embodiments suggests that a hyper-osmotic formulation may release the active ingredient of the therapeutic agent into the vitreous somewhat faster initially when the solutes of the injected formulation equilibrate with the osmolatiry of the vitreous, and that a hypo-osmotic formulation such as Avastin™ may release the active ingredient of the therapeutic agent into the vitreous somewhat slower initially when the solutes of the injected formulation equilibrate with the eye. A person of ordinary skill in the art can conduct experiments based on the teaching described herein to determine empirically the appropriate reservoir chamber volume and porous structure for a formulation of therapeutic agent disposed in the reservoir chamber, so as to release therapeutic amounts of the therapeutic agent for an extended time and to provide therapeutic concentrations of therapeutic agent in the vitreous within a range of therapeutic concentrations that is above the minimum inhibitory concentration for the extended time.

The therapeutic device may comprise at least one structure configured to provide safety precautions. The device may comprise at least one structure to prevent at least one of macrophage or other immune cell within the reservoir body; bacterial penetration; or retinal detachment.

The therapeutic device may be configured for other applications in the body. Other routes of administration of drugs may include at least one of intraocular, oral, subcutaneous, intramuscular, intraperitoneal, intranasal, dermal, intrathecal, intravascular, intra articular, pericardial, intraluminal in organs and gut or the like.

Conditions that may be treated and/or prevented using the drug delivery device and method described herein may include at least one of the following: hemophilia and other blood disorders, growth disorders, diabetes, leukemia, hepatitis, renal failure, HIV infection, hereditary diseases such as cerebrosidase deficiency and adenosine deaminase deficiency, hypertension, septic shock, autoimmune diseases such as multiple sclerosis, Graves disease, systemic lupus erythematosus and rheumatoid arthritis, shock and wasting disorders, cystic fibrosis, lactose intolerance, Crohn's disease, inflammatory bowel disease, gastrointestinal or other cancers, degenerative diseases, trauma, multiple systemic conditions such as anemia, and ocular diseases such as, for example, retinal detachment, proliferative retinopathy, proliferative diabetic retinopathy, degenerative disease, vascular diseases, occlusions, infection caused by penetrating traumatic injury, endophthalmitis such as endogenous/systemic infection, post-operative infections, inflammations such as posterior uveitis, retinitis or choroiditis and tumors such as neoplasms and retinoblastoma.

Examples of therapeutic agents 110 that may be delivered by the therapeutic device 100 are described in Table 1A and may include Triamcinolone acetonide, Bimatoprost (Lumigan), Ranibizumab (Lucentis™), Travoprost (Travatan, Alcon), Timolol (Timoptic, Merck), Levobunalol (Betagan, Allergan), Brimonidine (Alphagan, Allergan), Dorzolamide (Trusopt, Merck), Brinzolamide (Azopt, Alcon). Additional examples of therapeutic agents that may be delivered by the therapeutic device include antibiotics such as tetracycline, chlortetracycline, bacitracin, neomycin, polymyxin, gramicidin, cephalexin, oxytetracycline, chloramphenicol kanamycin, rifampicin, ciprofloxacin, tobramycin, gentamycin, erythromycin and penicillin; antifungals such as amphotericin B and miconazole; anti-bacterials such as sulfonamides, sulfadiazine, sulfacetamide, sulfamethizole and sulfisoxazole, nitrofurazone and sodium propionate; antivirals such as idoxuridine, trifluorotymidine, acyclovir, ganciclovir and interferon; antiallergenics such as sodium cromoglycate, antazoline, methapyriline, chlorpheniramine, pyrilamine, cetirizine and prophenpyridamine; anti-inflammatories such as hydrocortisone, hydrocortisone acetate, dexamethasone, dexamethasone 21-phosphate, fluocinolone, medrysone, prednisolone, prednisolone 21-phosphate, prednisolone acetate, fluoromethalone, betamethasone, and triamcinolone; non-steroidal anti-inflammatories such as salicylate, indomethacin, ibuprofen, diclofenac, flurbiprofen and piroxicam; decongestants such as phenylephrine, naphazoline and tetrahydrozoline; miotics and anticholinesterases such as pilocarpine, salicylate, acetylcholine chloride, physostigmine, eserine, carbachol, diisopropyl fluorophosphate, phospholine iodide and demecarium bromide; mydriatics such as atropine sulfate, cyclopentolate, homatropine, scopolamine, tropicamide, eucatropine and hydroxyamphetamine; sypathomimetics such as epinephrine; antineoplastics such as carmustine, cisplatin and fluorouracil; immunological drugs such as vaccines and immune stimulants; hormonal agents such as estrogens, estradiol, progestational, progesterone, insulin, calcitonin, parathyroid hormone and peptide and vasopressin hypothalamus releasing factor; beta adrenergic blockers such as timolol maleate, levobunolol Hcl and betaxolol Hcl; growth factors such as epidermal growth factor, fibroblast growth factor, platelet derived growth factor, transforming growth factor beta, somatotropin and fibronectin; carbonic anhydrase inhibitors such as dichlorophenamide, acetazolamide and methazolamide and other drugs such as prostaglandins, antiprostaglandins and prostaglandin precursors. Other therapeutic agents known to those skilled in the art which are capable of controlled, sustained release into the eye in the manner described herein are also suitable for use in accordance with embodiments of the present invention.

The therapeutic agent 110 may comprise one or more of the following: Abarelix, Abatacept, Abciximab, Adalimumab, Aldesleukin, Alefacept, Alemtuzumab, Alpha-1-proteinase inhibitor, Alteplase, Anakinra, Anistreplase, Antihemophilic Factor, Antithymocyte globulin, Aprotinin, Arcitumomab, Asparaginase, Basiliximab, Becaplermin, Bevacizumab, Bivalirudin, Botulinum Toxin Type A, Botulinum Toxin Type B, Capromab, Cetrorelix, Cetuximab, Choriogonadotropin alfa, Coagulation Factor IX, Coagulation factor VIIa, Collagenase, Corticotropin, Cosyntropin, Cyclosporine, Daclizumab, Darbepoetin alfa, Defibrotide, Denileukin diftitox, Desmopressin, Dornase Alfa, Drotrecogin alfa, Eculizumab, Efalizumab, Enfuvirtide, Epoetin alfa, Eptifibatide, Etanercept, Exenatide, Felypressin, Filgrastim, Follitropin beta, Galsulfase, Gemtuzumab ozogamicin, Glatiramer Acetate, Glucagon recombinant, Goserelin, Human Serum Albumin, Hyaluronidase, Ibritumomab, Idursulfase, Immune globulin, Infliximab, Insulin Glargine recombinant, Insulin Lyspro recombinant, Insulin recombinant, Insulin, porcine, Interferon Alfa-2a, Recombinant, Interferon Alfa-2b, Recombinant, Interferon alfacon-1, Interferon alfa-n1, Interferon alfa-n3, Interferon beta-1b, Interferon gamma-1b, Lepirudin, Leuprolide, Lutropin alfa, Mecasermin, Menotropins, Muromonab, Natalizumab, Nesiritide, Octreotide, Omalizumab, Oprelvekin, OspA lipoprotein, Oxytocin, Palifermin, Palivizumab, Panitumumab, Pegademase bovine, Pegaptanib, Pegaspargase, Pegfilgrastim, Peginterferon alfa-2a, Peginterferon alfa-2b, Pegvisomant, Pramlintide, Ranibizumab, Rasburicase, Reteplase, Rituximab, Salmon Calcitonin, Sargramostim, Secretin, Sermorelin, Serum albumin iodonated, Somatropin recombinant, Streptokinase, Tenecteplase, Teriparatide, Thyrotropin Alfa, Tositumomab, Trastuzumab, Urofollitropin, Urokinase, or Vasopressin. The molecular weights of the molecules and indications of these therapeutic agents are set for below in Table 1A, below.

The therapeutic agent 110 may comprise one or more of compounds that act by binding members of the immunophilin family of cellular proteins. Such compounds are known as “immunophilin binding compounds.” Immunophilin binding compounds include but are not limited to the “limus” family of compounds. Examples of limus compounds that may be used include but are not limited to cyclophilins and FK506-binding proteins (FKBPs), including sirolimus (rapamycin) and its water soluble analog SDZ-RAD, tacrolimus, everolimus, pimecrolimus, CCI-779 (Wyeth), AP23841 (Ariad), and ABT-578 (Abbott Laboratories).

The limus family of compounds may be used in the compositions, devices and methods for the treatment, prevention, inhibition, delaying the onset of, or causing the regression of angiogenesis-mediated diseases and conditions of the eye, including choroidal neovascularization. The limus family of compounds may be used to prevent, treat, inhibit, delay the onset of, or cause regression of AMD, including wet AMD. Rapamycin may be used to prevent, treat, inhibit, delay the onset of, or cause regression of angiogenesis-mediated diseases and conditions of the eye, including choroidal neovascularization. Rapamycin may be used to prevent, treat, inhibit, delay the onset of, or cause regression of AMD, including wet AMD.

The therapeutic agent 110 may comprise one or more of: pyrrolidine, dithiocarbamate (NF.kappa.B inhibitor); squalamine; TPN 470 analogue and fumagillin; PKC (protein kinase C) inhibitors; Tie-1 and Tie-2 kinase inhibitors; inhibitors of VEGF receptor kinase; proteosome inhibitors such as Velcade™ (bortezomib, for injection; ranibuzumab (Lucentis™) and other antibodies directed to the same target; pegaptanib (Macugen™); vitronectin receptor antagonists, such as cyclic peptide antagonists of vitronectin receptor-type integrins; .alpha.-v/.beta.-3 integrin antagonists; .alpha.-v/.beta.-1 integrin antagonists; thiazolidinediones such as rosiglitazone or troglitazone; interferon, including .gamma.-interferon or interferon targeted to CNV by use of dextran and metal coordination; pigment epithelium derived factor (PEDF); endostatin; angiostatin; tumistatin; canstatin; anecortave acetate; acetonide; triamcinolone; tetrathiomolybdate; RNA silencing or RNA interference (RNAi) of angiogenic factors, including ribozymes that target VEGF expression; Accutane™ (13-cis retinoic acid); ACE inhibitors, including but not limited to quinopril, captopril, and perindozril; inhibitors of mTOR (mammalian target of rapamycin); 3-aminothalidomide; pentoxifylline; 2-methoxyestradiol; colchicines; AMG-1470; cyclooxygenase inhibitors such as nepafenac, rofecoxib, diclofenac, rofecoxib, NS398, celecoxib, vioxx, and (E)-2-alkyl-2(4-methanesulfonylphenyl)-1-phenylethene; t-RNA synthase modulator; metalloprotease 13 inhibitor; acetylcholinesterase inhibitor; potassium channel blockers; endorepellin; purine analog of 6-thioguanine; cyclic peroxide ANO-2; (recombinant) arginine deiminase; epigallocatechin-3-gallate; cerivastatin; analogues of suramin; VEGF trap molecules; apoptosis inhibiting agents; Visudyne™, snET2 and other photo sensitizers, which may be used with photodynamic therapy (PDT); inhibitors of hepatocyte growth factor (antibodies to the growth factor or its receptors, small molecular inhibitors of the c-met tyrosine kinase, truncated versions of HGF e.g. NK4).

The therapeutic agent 110 may comprise a combination with other therapeutic agents and therapies, including but not limited to agents and therapies useful for the treatment of angiogenesis or neovascularization, particularly CNV. Non-limiting examples of such additional agents and therapies include pyrrolidine, dithiocarbamate (NF.kappa.B inhibitor); squalamine; TPN 470 analogue and fumagillin; PKC (protein kinase C) inhibitors; Tie-1 and Tie-2 kinase inhibitors; inhibitors of VEGF receptor kinase; proteosome inhibitors such as Velcade™ (bortezomib, for injection; ranibuzumab (Lucentis™) and other antibodies directed to the sametarget; pegaptanib (Macugen™); vitronectin receptor antagonists, such as cyclic peptide antagonists of vitronectin receptor-type integrins; .alpha.-v/.beta.-3 integrin antagonists; .alpha.-v/.beta.-1 integrin antagonists; thiazolidinediones such as rosiglitazone or troglitazone; interferon, including .gamma.-interferon or interferon targeted to CNV by use of dextran and metal coordination; pigment epithelium derived factor (PEDF); endostatin; angiostatin; tumistatin; canstatin; anecortave acetate; acetonide; triamcinolone; tetrathiomolybdate; RNA silencing or RNA interference (RNAi) of angiogenic factors, including ribozymes that target VEGF expression; Accutane™ (13-cis retinoic acid); ACE inhibitors, including but not limited to quinopril, captopril, and perindozril; inhibitors of mTOR (mammalian target of rapamycin); 3-aminothalidomide; pentoxifylline; 2-methoxyestradiol; colchicines; AMG-1470; cyclooxygenase inhibitors such as nepafenac, rofecoxib, diclofenac, rofecoxib, NS398, celecoxib, vioxx, and (E)-2-alkyl-2(4-methanesulfonylphenyl)-1-phenylethene; t-RNA synthase modulator; metalloprotease 13 inhibitor; acetylcholinesterase inhibitor; potassium channel blockers; endorepellin; purine analog of 6-thioguanine; cyclic peroxide ANO-2; (recombinant) arginine deiminase; epigallocatechin-3-gallate; cerivastatin; analogues of suramin; VEGF trap molecules; inhibitors of hepatocyte growth factor (antibodies to the growth factor or its receptors, small molecular inhibitors of the c-met tyrosine kinase, truncated versions of HGF e.g. NK4); apoptosis inhibiting agents; Visudyne™, snET2 and other photo sensitizers with photodynamic therapy (PDT); and laser photocoagulation.

The therapeutic agents may be used in conjunction with a pharmaceutically acceptable carrier such as, for example, solids such as starch, gelatin, sugars, natural gums such as acacia, sodium alginate and carboxymethyl cellulose; polymers such as silicone rubber; liquids such as sterile water, saline, dextrose, dextrose in water or saline; condensation products of castor oil and ethylene oxide, liquid glyceryl triester of a lower molecular weight fatty acid; lower alkanols; oils such as corn oil, peanut oil, sesame oil, castor oil, and the like, with emulsifiers such as mono- or di-glyceride of a fatty acid, or a phosphatide such as lecithin, polysorbate 80, and the like; glycols and polyalkylene glycols; aqueous media in the presence of a suspending agent, for example, sodium carboxymethylcellulose, sodium hyaluronate, sodium alginate, poly(vinyl pyrrolidone) and similar compounds, either alone, or with suitable dispensing agents such as lecithin, polyoxyethylene stearate and the like. The carrier may also contain adjuvants such as preserving, stabilizing, wetting, emulsifying agents or other related materials.

The therapeutic device may comprise a container configured to hold at least one therapeutic agent, the container comprising a chamber to hold the at least one therapeutic agent with at least one opening to release the at least one therapeutic agent to the vitreous humor and porous structure 150 placed within the at least one opening. The porous structure 150 may comprise a fixed tortuous, porous material such as a sintered metal, a sintered glass or a sintered polymer with a defined porosity and tortuosity that controls the rate of delivery of the at least one therapeutic agent to the vitreous humor. The rigid porous structures provide certain advantages over capillary tubes, erodible polymers and membranes as a mechanism for controlling the release of a therapeutic agent or agents from the therapeutic device. These advantages include the ability of the rigid porous structure to comprise a needle stop, simpler and more cost effective manufacture, flushability for cleaning or declogging either prior to or after implantation, high efficiency depth filtration of microorganisms provided by the labyrinths of irregular paths within the structure and greater robustness due to greater hardness and thickness of the structure compared to a membrane or erodible polymer matrix. Additionally, when the rigid porous structure is manufactured from a sintered metal, ceramic, glass or certain plastics, it can be subjected to sterilization and cleaning procedures, such as heat or radiation based sterilization and depyrogenation, that might damage polymer and other membranes. In certain embodiments, as illustrated in example 9, the rigid porous structure may be configured to provide a therapeutically effective, concentration of the therapeutic agent in the vitreous for at least 6 months. This release profile provided by certain configurations of the rigid porous structures enables a smaller device which can be preferred in a small organ such as the eye where larger devices may alter or impair vision.

Tuning of Therapeutic Device for Sustained Release Based on an Injection of a Formulation

The therapeutic device 100 can be tuned to deliver a target therapeutic concentration profile based on the volume of formulation injected into the device, for example as described in U.S. patent application Ser. No. 12/696,678, Pub. No. 2010/0255061, the full disclosure of which has been previously incorporated by reference. The injected volume may comprise a substantially fixed volume, for example within about +/−30% of an intended pre-determined target volume. The volume of the reservoir can be sized with the release rate index so as to release the therapeutic agent for an extended time substantially greater than the treatment time of a corresponding bolus injection. The device can also be tuned to release the therapeutic agent based on the half life of the therapeutic agent in the eye. The device volume and release rate index comprise parameters that can be tuned together based on the volume of formulation injected and the half life of the therapeutic agent in the eye. The following equations can be used to determine therapeutic device parameters suitable for tuning the device.

Rate=Vr(dCr/dt)=−D(PA/TL)Cr

where Rate=Rate of release of therapeutic agent from device Cr=concentration of therapeutic agent in reservoir Vr=volume of reservoir D=Diffusion constant

PA/TL=RRI

P=porosity A=area T=tortuosity=F=channel parameter. For a substantially fixed volume injection,

Cr0=(Injection Volume)(Concentration of Formulation)/Vr

Where Cr0=initial concentration in reservoir following injection of formulation

For Injection Volume=50 uL

Cr0=(0.05 mL)(10 mg/mL)/Vr(1000 ug/1 mg)=500 ug/Vr

Rate=x(500 ug)exp(−xt)

where t=time

x=(D/Vr)(PA/TL)

With a mass balance on the vitreous

Vv(dCv/dt)=Rate from device=kVvCv

where Vv=volume of vitreous (about 4.5 ml) Cv=concentration of therapeutic agent in vitreous k=rate of drug from vitreous (proportional to 1/half life of drug in vitreous) For the situation appropriate for the embodiments as described herein where Cv remains substantially constant and changes slowly with time (i.e. dCv/dt is approximately 0),

Cv=(Rate from device)/(kVv)

Since kVv is substantially constant, the max value of Cv will correspond to conditions that maximize the Rate from the device. At a given time since injection into the device (e.g., 180 days), the maximum Cv is found at the value of x that provides the maximum rate. The optimal value of x satisfies

d(Rate)/dx=0 at a given time.

Rate=500(x)exp(−xt)=f(x)g(x) where f(x)=500x and g(x)=exp(−xt)

d(Rate)/dx=f′(x)g′(x)+f(x)g′(x)=500(1−xt)exp(−xt)

For a given time, t, d(Rate)/dx=0 when 1−xt=0 and xt=1 The rate is maximum when (D/Vr)(PA/TL)t=1. For a given volume, optimal PA/TL=optimal RRI=Vr/(Dt) Therefore the highest Cv at a given time, t, occurs for the optimal RRI=(PA/FL) for a given Vr. Also, the ratio (Vr)/(RRI)=(Vr)/(PA/TL)=Dt will determine the optimal rate at the time.

The above equations provide approximate optimized values that, when combined with numerical simulations, can provide optimal values of Vr and PA/TL. The final optimum value can depend on additional parameters, such as the filling efficiency.

The above parameters can be used to determine the optimal RRI, and the therapeutic device can be tuned to the volume of formulation injected into the device with a device reservoir volume and release rate index within about +/−50% of the optimal values, for example +/−30% of the optimal values. For example, for an optimal release rate index of the porous structure and an optimal reservoir volume sized to receive a predetermined quantity of therapeutic agent, e.g. 50 uL, so as to achieve therapeutic concentrations above a minimum inhibitory concentration for a predetermined extended time such as 90 days, the maximum volume of the reservoir can be limited to no more than about twice the optimal volume. This tuning of the reservoir volume and the porous structure to the injected volume of the commercially available formulation can increase the time of release of therapeutic amounts from the device as compared to a much larger reservoir volume that receives the same volume of commercially available injectable formulation. Although many examples as described herein show a porous fit structure and reservoir volume tuned together to receive a quantity of formulation and provide release for an extended time, the porous structure tuned with the reservoir may comprise one or more of a porous frit, a permeable membrane, a semi-permeable membrane, a capillary tube or a tortuous channel, nano-structures, nano-channels or sintered nano-particles, and a person of ordinary skill in the art can determine the release rate characteristics, for example a release rate index, so as to tune the one or more porous structures and the volume to receive the quantity of the formulation and release therapeutic amounts for an extended time.

As an example, the optimal RRI at 180 days can be determined for a reservoir volume of about 125 uL. Based on the above equations (Vr/Dt)=optimal RRI, such that the optimal RRI at 180 days is about 0.085 for the 50 uL formulation volume injected into the device. The corresponding Cv is about 3.19 ug/mL at 180 days based on the Rate of drug released from the device at 180 days and the rate of the drug from the vitreous (k corresponding to a half life of about 9 days). A device with a container reservoir volume of 63 uL and RRI of 0.044 will also provide the optimal Cv at 180 days since the ratio of Vr to PA/TL is also optimal. Although an optimal value can be determined, the therapeutic device can be tuned to provide therapeutic amounts of drug at a targeted time, for example 180 days, with many values of the reservoir volume and many values of the release rate index near the optimal values, for example within about +/−50% of the optimal values. Although the volume of the reservoir can be substantially fixed, the volume of the reservoir can vary, for example within about +/−50% as with an expandable reservoir such as a balloon reservoir.

The half life of the drug in the vitreous humor of the eye can be determined based on the therapeutic agent and the type of eye, for example human, rabbit or monkey, such that the half life may be determined based on the species of the eye, for example. With at least some animal models the half life of the therapeutic agent in the vitreous humor can be shorter than for human eyes, for example by a factor of about two in at least some instances. For example, the half-life of the therapeutic agent Lucentis™ (ranibizumab) can be about nine days in the human eye and about two to four days in the rabbit and monkey animal models. For small molecules, the half life in the vitreous humor of the human eye can be about two to three hours and can be about one hour in the monkey and rabbit animal models. The therapeutic device can be tuned to receive the volume of formulation based on the half life of the therapeutic agent in the human vitreous humor, or an animal vitreous humor, or combinations thereof. Based on the teachings described herein, a person of ordinary skill in the art can determine empirically the half life of the therapeutic agent in the eye based on the type of eye and the therapeutic agent, such that the reservoir and porous structure can be tuned together so as to receive the volume of formulation and provide therapeutic amounts for the extended time.

Combined Therapeutic Agent Treatments

The therapeutic agents and devices as described herein can be used to deliver combinations of therapeutic agents for an extended time. The combined therapeutic agents can be used to treat many disease of the eye, for example age related macular degeneration (hereinafter “AMD”).

The embodiments as described herein may incorporate one or more components of the methods and apparatus described in U.S. application Ser. No. 12/696,678, filed Jan. 29, 2010, entitled “Posterior Segment Drug Delivery”, U.S. Pat. App. Pub. No. 2010/0255061 (attorney docket not. 026322-003750US), the full disclosure of which has been previously incorporated herein by reference.

As used herein, like numerals and letters denote like apparatus structures and like method steps, for example as combined with like structures and method steps of U.S. application Ser. No. 12/696,678, in accordance with embodiments as described herein.

Combination therapy to treat AMD may be can be used to treat a patient through the different disease stages. Early in the AMD disease an inflammatory and oxidative stress takes a role in the development of the early and intermediate stage of the disease. When an advanced stage of AMD develops, the advanced stage may comprise enhanced by the VEGF activity and inflammatory components. When choroidal neovascularization (hereinafter “CNV”) is under successful control of the treating physician there can be a benefit to controlling scar development and recurrence of the CNV (˜50%) due to an ongoing inflammatory stress.

Combination therapy to treat AMD may comprise means for placing one or more of the sustained release therapeutic device 100 as described herein that can host various compounds either in combination or sequentially, or combinations thereof, based on the disease stage and targeted therapeutic treatment.

For example: A patient with early stage AMD who is at risk for advancing to intermediate or advanced AMD may benefit from an anti inflammatory treatment such as complement inhibitor alone or in combination with an anti oxidant. If the disease advances to CNV the same device may be injected with AntiVEGF alone or in combination with any anti-inflammatory agent. Subsequently when the CNV is under successful control an agent to control local inflammation such as COX inhibitor can be injected to the device to reduce the chances for fibrosis and recurrence.

Therapeutic agents to treat stages of AMD.

-   -   1. An AMD patient may go through few different disease stages,         and one or more combinations of therapeutic devices or agents         can be used to treat each stage of the disease. One or more         corresponding therapeutic agent can be injected to treat         neovascularization and inflammation, appropriate to the         condition of the eye.         -   a. Early/Intermediate AMD—Mainly manifested by presence of             Drusen (also referred to as dry AMD)         -   b. Advanced AMD (also referred to as wet AMD)             -   i. CNV                 -   1. New CNV                 -   2. CNV recurrence following successful treatment                     cycle             -   ii. Geographic Atrophy     -   2. Inflammation may play a role in all these stages, and an         anti-inflammatory treatment agent can be used at each stage         -   a. Genetic variability of the complement system may causes             defective regulation of the complement system. Enhanced             complement activity may increase inflammation which in turn             increases VEGF expression and CNV development. The             therapeutic agent injected into device 100 can be injected             based on a response of the patient to treatment.         -   b. Complement factors have been found in both Drusen and CNV             and can contribute to cell apoptosis.         -   c. An inflammatory component is present while CNV is             regressing and may contribute to scar formation which can             cause additional retinal damage. An antiinflammatory can be             injected into to inhibit scar formation.     -   3. Oxidative stress may cause both early stage AMD and can be         associated with the transformation of Intermediate to advanced         AMD     -   4. Anti inflammatory agents having an effect on the wet stage of         AMD and suitable for injection into therapeutic device 100         include one or more of:         -   a. Steroids         -   b. Tumor necrosis factor (hereinafter “TNF”) inhibitors         -   c. COX inhibitors     -   5. Complement system inhibitors can be combined in accordance         with embodiments described herein for the treatment of early,         intermediate and advanced stages of AMD

The combination therapy to treat AMD may comprise one or more of injecting the therapeutic agent 110 directly into the vitreous humor from a needle, injecting the therapeutic agent into therapeutic device 100 to store the therapeutic agent in device 100, injecting the therapeutic agent into the device 100 and through a porous structure to deliver a bolus of therapeutic agent 110 and store therapeutic agent 110 in device 100, injecting a first therapeutic agent 110 into a first device 100 and a second therapeutic agent 110 into a second therapeutic device 100. Below Table 2 shows combinations treatments in accordance with embodiments.

TABLE 2 Combinations of therapeutic agent injections and devices First Therapeutic Agent: Second Therapeutic agent: Vascularization Inhibitor NSAID Combination (e.g VEGF Inhib) (e.g. Oxygenase Inhibitor) 1 Injected into Device 1 when Injected into Device 1 when implanted implanted 2 Injected into Device 1 when Solid on inside of device implanted when implanted 3 Injected into Device 1 when solid on outside of device implanted when implanted 4 Injected into Device 1 when solid suspension injected into implanted device first chamber of device when implanted 5 Injected into Device 1 when solid suspension injected into implanted second chamber of device when implanted 6 Injected into Device 1 when Injected into Device 2 when implanted impalnted 7 Injected into Device 1 when Injected into Vitreous Humor implanted 8 Injected into Vitreous Injected into Device 2 Humor 9 Injected into Vitreous Injected into Vitreous Humor Humor

The combinations shown in Table 2 can be used in many ways to treat the patient.

FIG. 2 shows a first therapeutic agent 110A contained in a first injector 187 and a second therapeutic agent 110B contained in a second injector 187 to treat the patient. The first therapeutic agent 110A can be combined with the second therapeutic agent 110B to treat the eye. The first therapeutic agent 110A and the second therapeutic agent 110B can be injected into the vitreous humor of the eye. The first therapeutic agent 110A may comprise a therapeutic agent to inhibit neoplasia, for example to inhibit neovascularization such as a VEGF inhibitor. The second therapeutic agent 110B may comprise an antiinflammatory, for example a steroid or a non-steroidal antiinflammatory such as a COX inhibitor. While the first therapeutic agent and the second therapeutic agent can be delivered in many ways, the first therapeutic agent and the second therapeutic agent may each be injected directly into the vitreous humor with a needle of the injector.

FIG. 3 shows a first therapeutic agent 110A contained in a first injector 187 injected directly into the vitreous humor of the eye and a second therapeutic agent 110B contained in a second injector 187 injected into therapeutic device 100 so as to treat the patient. The therapeutic device can be configured to release first therapeutic agent 110A for an extended time as described herein. The first therapeutic agent may comprise the agent to inhibit neoplasia and the second therapeutic agent may comprise the antiinflammatory. Alternatively, the second therapeutic agent may comprise the agent to inhibit neoplasia and the first therapeutic agent may comprise the antiinflammatory.

FIG. 4 shows a plurality of therapeutic devices implanted into the eye to deliver therapeutic amounts of first therapeutic agent 110A and second therapeutic agent 110B. The plurality of therapeutic devices comprises a first therapeutic device 100 and a second therapeutic device 100. The first therapeutic device 100 can be configured with a volume and release rate index to provide sustained release of the first therapeutic agent when the first therapeutic agent 110A is injected into first device 100 implanted in the eye, and the second therapeutic device 100 can be configured with a second volume and second release rate index to provide sustained release of the second therapeutic agent 110B when the second device 100 is implanted in the eye.

FIG. 5 shows a therapeutic device having a plurality of parallel reservoirs comprising a first reservoir 140A and a second reservoir 140B. First reservoir 140A comprises a first container 130A having a first chamber 132A coupled to a first porous structure 150X. Second reservoir 140B comprises a second container 130B having a second chamber 132B coupled to a second porous structure 150Y. A first injector 187A can comprise a first amount of therapeutic agent 110A and can be coupled to first reservoir 140A to deliver therapeutic amounts of first therapeutic agent 110A. A second injector 187B can comprise a second amount of second therapeutic agent 110B and can be coupled to second reservoir 140B to deliver therapeutic amounts of second therapeutic agent 110B. Each of the first container and the second container can be tuned to the amount of therapeutic agent injected into the respective container as described herein. The first chamber 132A can be configured with a volume and the first porous structure 150X configured release rate index so as to provide sustained release of the first therapeutic agent 110A when the first therapeutic agent 110A is injected into first device 100 implanted in the eye. The second chamber 132B can be configured with a second volume and the second porous structure 150Y can be configured with a second release rate index so as to provide sustained release of the second therapeutic agent 110B when the second therapeutic agent 110B is injected into device 100 implanted in the eye. Barrier 160 may extend between first chamber 132A and second chamber 132B. Based on the teachings described herein a person of ordinary skill in the art can determine the volume and release rate index of each chamber so as to release the therapeutic agent for the extended time.

FIG. 6A shows a therapeutic device having a plurality of reservoirs configured in series comprising a first reservoir 140A and a second reservoir 140B. First reservoir 140A comprises a first container 130A having a first chamber 132A coupled to a first porous structure 150X. Second reservoir 140B comprises a second container 130B having a second chamber 132B coupled to a second porous structure 150Y. A injector 187 can comprise a first amount of therapeutic agent 110A and can be coupled to first reservoir 140A to inject therapeutic amounts of first therapeutic agent 110A. Second injector 132B can comprise a second amount of second therapeutic agent 110B comprising a solid located within second reservoir 140B so as to deliver therapeutic amounts of first therapeutic agent 110A. The first container can be tuned to the amount of therapeutic agent injected into chamber 132A. The first chamber 132A can be configured with a volume and the first porous structure 150X configured release rate index so as to provide sustained release of the first therapeutic agent 110A when the first therapeutic agent 110A is injected into first device 100 implanted in the eye. The second chamber 132B can be configured with a second volume and the second porous structure 150Y configured with a second release rate index so as to provide sustained release of the solid second therapeutic agent 110B and first therapeutic agent 110A. The first porous structure 150X may extend between first chamber 132A and second chamber 132B, and the porosity and RRI of the first porous structure 150X can be smaller than the porosity and RRI of the second porous structure 150Y such that release rate of the first therapeutic agent 110A is substantially determined based on the porosity and RRI of the first porous structure and the release rate of the second therapeutic agent is determined substantially based on the porosity and RRI of the second porous structure. Although the first therapeutic agent 110A can be released serially through the first porous structure 150X followed by release through the second porous structure 150Y, the porosity and RRI of the second porous structure 150Y can be substantially greater than the first porous structure 150X such that the release rate profile of the first therapeutic agent can be determined substantially based on the first RRI and first porosity of the first porous structure 150X. The second chamber 132B may comprise a sufficient amount of the solid second therapeutic agent such that the solid can remain in the second chamber for a plurality of injections of the first therapeutic agent, for example can remain in the second chamber 132B for at least about one year when the device 100 is implanted in the eye. The first chamber may comprise an antineoplastic agent, for example a VEGF inhibitor such as Luentis™, and the second chamber may comprise an antiinflammatory, for example a non-steroidal anti-inflammatory such as a COX inhibitor, for example such as celocoxib. Based on the teachings described herein a person of ordinary skill in the art could conduct experiments and simulations to determine the first release rate index, volume of the first chamber, and the first injected amount so as to release the first therapeutic agent 110A for a first extended time, and determine the second release rate index, volume of the second chamber, and the second amount of second therapeutic agent 110B so as to release the first therapeutic agent 110A for the first extended time the second therapeutic agent 110B for the second extended time.

FIG. 6B shows a rigid porous structure as in FIG. 6A. The rigid porous structure 158 comprises a plurality of interconnecting channels 156. The porous structure comprises a sintered material composed of interconnected grains 155 of material. The interconnected grains of material define channels that extend through the porous material to release the therapeutic agent. The channels may extend around the sintered grains of material, such that the channels comprise interconnecting channels extending through the porous material.

The rigid porous structure can be configured for injection of the therapeutic agent into the container in many ways. The channels of the rigid porous structure may comprise substantially fixed channels when the therapeutic agent is injected into the reservoir with pressure. The rigid porous structure comprises a hardness parameter within a range from about 160 Vickers to about 500 Vickers. In some embodiments the rigid porous structure is formed from sintered stainless steel and comprises a hardness parameter within a range from about 200 Vickers to about 240 Vickers. In some embodiments it is preferred to inhibit ejection of the therapeutic agent through the porous structure during filling or refilling the reservoir of the therapeutic device with a fluid. In these embodiments the channels of the rigid porous structure comprise a resistance to flow of an injected solution or suspension through a thirty gauge needle such that ejection of said solution or suspension through the rigid porous structure is substantially inhibited when said solution or suspension is injected into the reservoir of the therapeutic device. Additionally, these embodiments may optionally comprise an evacuation vent or an evacuation reservoir under vacuum or both to facilitate filling or refilling of the reservoir.

The reservoir and the porous structure can be configured to release therapeutic amounts of the therapeutic agent in many ways. The reservoir and the porous structure can be configured to release therapeutic amounts of the therapeutic agent corresponding to a concentration of at least about 0.1 ug per ml of vitreous humor for an extended period of at least about three months. The reservoir and the porous structure can be configured to release therapeutic amounts of the therapeutic agent corresponding to a concentration of at least about 0.1 ug per ml of vitreous humor and no more than about 10 ug per ml for an extended period of at least about three months. The therapeutic agent may comprise at least a fragment of an antibody and a molecular weight of at least about 10 k Daltons. For example, the therapeutic agent may comprise one or more of ranibizumab or bevacizumab. Alternatively or in combination, the therapeutic agent may comprise a small molecule drug suitable for sustained release. The reservoir and the porous structure may be configured to release therapeutic amounts of the therapeutic agent corresponding to a concentration of at least about 0.1 ug per ml of vitreous humor and no more than about 10 ug per ml for an extended period of at least about 3 months or at least about 6 months. The reservoir and the porous structure can be configured to release therapeutic amounts of the therapeutic agent corresponding to a concentration of at least about 0.1 ug per ml of vitreous humor and no more than about 10 ug per ml for an extended period of at least about twelve months or at least about two years or at least about three years. The reservoir and the porous structure may also be configured to release therapeutic amounts of the therapeutic agent corresponding to a concentration of at least about 0.01 ug per ml of vitreous humor and no more than about 300 ug per ml for an extended period of at least about 3 months or 6 months or 12 months or 24 months.

The channels of the rigid porous structure comprise a hydrogel configured to limit a size of molecules passed through the channels of the rigid porous structure. For example, the hydrogel can be formed within the channels and may comprise an acrylamide gel. The hydrogel comprises a water content of at least about 70%. For example, the hydrogel may comprise a water content of no more than about 90% to limit molecular weight of the therapeutic agent to about 30 k Daltons. The hydrogel comprises a water content of no more than about 95% to limit molecular weight of the therapeutic agent to about 100 k Daltons. The hydrogel may comprise a water content within a range from about 90% to about 95% such that the channels of the porous material are configured to pass Lucentis™ and substantially not pass Avastin™.

The rigid porous structure may comprise a composite porous material that can readily be formed in or into a wide range of different shapes and configurations. For example, the porous material can be a composite of a metal, aerogel or ceramic foam (i.e., a reticulated inter-cellular structure in which the interior cells are interconnected to provide a multiplicity of pores passing through the volume of the structure, the walls of the cells themselves being substantially continuous and non-porous, and the volume of the cells relative to that of the material forming the cell walls being such that the overall density of the intercellular structure is less than about 30 percent theoretical density) the through pores of which are impregnated with a sintered powder or aerogel. The thickness, density, porosity and porous characteristics of the final composite porous material can be varied to conform with the desired release of the therapeutic agent.

Embodiments comprise a method of making an integral (i.e., single-component) porous structure. The method may comprise introducing particles into a mold having a desired shape for the porous structure. The shape includes a proximal end defining a plurality of proximal porous channel openings to couple to the reservoir, a distal end defining a plurality of outlet channel openings to couple to the vitreous humor of the eye, a plurality of blind inlet cavities extending into the filter from the proximal openings, and a plurality of blind outlet cavities extending into the porous structure from the outlet channel openings. The method further includes applying pressure to the mold, thereby causing the particles to cohere and form a single component, and sintering the component to form the porous structure. The particles can be pressed and cohere to form the component without the use of a polymeric binder, and the porous structure can be formed substantially without machining.

The mold can be oriented vertically with the open other end disposed upwardly, and metal powder having a particle size of less than 20 micrometers can be introduced into the cavity through the open end of the mold while vibrating the mold to achieve substantially uniform packing of the metal powder in the cavity. A cap can be placed on the open other end of the mold, and pressure is applied to the mold and thereby to the metal powder in the cavity to cause the metal powder to cohere and form a cup-shaped powdered metal structure having a shape corresponding to the mold. The shaped powdered metal structure can be removed from the mold, and sintered to obtain a porous sintered metal porous structure.

The metal porous structure can be incorporated into the device by a press fit into an impermeable structure with an opening configured to provide a tight fit with the porous structure. Other means, such as welding, known to those skilled in the art can be used to incorporate the porous structure into the device. Alternatively, or in combination, the powdered metal structure can be formed in a mold where a portion of the mold remains with the shaped powdered metal structure and becomes part of the device. This may be advantageous in achieving a good seal between the porous structure and the device.

The release rate of therapeutic agent through a porous body, such as a sintered porous metal structure or a porous glass structure, may be described by diffusion of the of the therapeutic agent within the porous structure with the channel parameter, and with an effective diffusion coefficient equal to the diffusion coefficient of the therapeutic agent in the liquid that fills the reservoir multiplied by the Porosity and a Channel Parameter of the porous body:

Release Rate=(DP/F)A(c _(R) −c _(V))/L, where:

c_(R)=Concentration in reservoir c_(V)=Concentration outside of the reservoir or in the vitreous D=Diffusion coefficient of the therapeutic agent in the reservoir solution P=Porosity of porous structure F=Channel parameter that may correspond to a tortuosity parameter of channels of porous structure A=Area of porous structure L=Thickness (length) of porous structure

Cumulative Release=1−cR/cR0=1−exp((−DPA/FLV _(R))t),

where t=time, Vr=reservoir volume

The release rate index can (hereinafter RRI) be used to determine release of the therapeutic agent. The RRI may be defined as (PA/FL), and the RRI values herein will have units of mm unless otherwise indicated. Many of the porous structures used in the therapeutic delivery devices described here have an RRI of no more than about 5.0, often no more than about 2.0, and can be no more than about 1.2 mm.

The channel parameter can correspond to an elongation of the path of the therapeutic agent released through the porous structure. The porous structure may comprise many interconnecting channels, and the channel parameter can correspond to an effective length that the therapeutic agent travels along the interconnecting channels of the porous structure from the reservoir side to the vitreous side when released. The channel parameter multiplied by the thickness (length) of the porous structure can determine the effective length that the therapeutic agent travels along the interconnecting channels from the reservoir side to the vitreous side. For example, the channel parameter (F) of about 1.5 corresponds to interconnecting channels that provide an effective increase in length traveled by the therapeutic agent of about 50%, and for a 1 mm thick porous structure the effective length that the therapeutic agent travels along the interconnecting channels from the reservoir side to the vitreous side corresponds to about 1.5 mm. The channel parameter (F) of at least about 2 corresponds to interconnecting channels that provide an effective increase in length traveled by the therapeutic agent of about 100%, and for a 1 mm thick porous structure the effective length that the therapeutic agent travels along the interconnecting channels from the reservoir side to the vitreous side corresponds to at least about 2.0 mm. As the porous structure comprises many interconnecting channels that provide many alternative paths for release of the therapeutic agent, blockage of some of the channels provides no substantial change in the effective path length through the porous structure as the alternative interconnecting channels are available, such that the rate of diffusion through the porous structure and the release of the therapeutic agent are substantially maintained when some of the channels are blocked.

If the reservoir solution is aqueous or has a viscosity similar to water, the value for the diffusion coefficient of the therapeutic agent (TA) in water at the temperature of interest may be used. The following equation can be used to estimate the diffusion coefficient at 37° C. from the measured value of D_(BSA,20C)=6.1 e-7 cm2/s for bovine serum albumin in water at 20° C. (Molokhia et al, Exp Eye Res 2008):

D _(TA,37C) =D _(BSA,20C)(η_(20C)/η_(37C))(MW _(BSA) /MW _(TA)) where

MW refers to the molecular weight of either BSA or the test compound and η is the viscosity of water, and Table 3 lists diffusion coefficients of proteins of interest.

TABLE 3 Diffusion Coefficients Diff Coeff Compound MW Temp C. (cm{circumflex over ( )}2/s) BSA 69,000 20 6.1E−07 BSA 69,000 37 9.1E−07 Ranibizumab 48,000 20 6.9E−07 Ranibizumab 48,000 37 1.0E−06 Bevacizumab 149,000 20 4.7E−07 Bevacizumab 149,000 37 7.1E−07 Small molecules have a diffusion coefficient similar to fluorescein (MW=330, D=4.8 to 6 e-6 cm²/s from Stay, M S et al. Pharm Res 2003, 20(1), pp. 96-102). For example, the small molecule may comprise a glucocorticoid such as triamcinolone acetonide having a molecular weight of about 435.

The porous structure comprises a porosity, a thickness, a channel parameter and a surface area configured to release therapeutic amounts for the extended period. The porous material may comprise a porosity corresponding to the fraction of void space of the channels extending within the material. The porosity comprises a value within a range from about 3% to about 70%. In other embodiments, the porosity comprises a value with a range from about 5% to about 10% or from about 10% to about 25%, or for example from about 15% to about 20%. Porosity can be determined from the weight and macroscopic volume or can be measured via nitrogen gas adsorption

The porous structure may comprise a plurality of porous structures, and the area used in the above equation may comprise the combined area of the plurality of porous structures.

The channel parameter may comprise a fit parameter corresponding to the tortuosity of the channels. For a known porosity, surface area and thickness of the surface parameter, the curve fit parameter F, which may correspond to tortuosity of the channels can be determined based on experimental measurements. The parameter PA/FL can be used to determine the desired sustained release profile, and the values of P, A, F and L determined. The rate of release of the therapeutic agent corresponds to a ratio of the porosity to the channel parameter, and the ratio of the porosity to the channel parameter can be less than about 0.5 such that the porous structure releases the therapeutic agent for the extended period. For example, the ratio of the porosity to the channel parameter is less than about 0.1 or for example less than about 0.2 such that the porous structure releases the therapeutic agent for the extended period. The channel parameter may comprise a value of at least about 1, such as at least about 1.2. For example, the value of the channel parameter may comprise at least about 1.5, for example at least about 2, and may comprise at least about 5. The channel parameter can be within a range from about 1.1 to about 10, for example within a range from about 1.2 to about 5. A person of ordinary skill in the art can conduct experiments based on the teachings described herein to determine empirically the channel parameter to release the therapeutic agent for an intended release rate profile.

The area in the model originates from the description of mass transported in units of flux; i.e., rate of mass transfer per unit area. For simple geometries, such as a porous disc mounted in an impermeable sleeve of equal thickness, the area corresponds to one face of the disc and the thickness, L, is the thickness of the disc. For more complex geometries, such as a porous body in the shape of a truncated cone, the effective area is a value in between the area where therapeutic agent enters the porous body and the area where therapeutic agent exits the porous body.

A model can be derived to describe the release rate as a function of time by relating the change of concentration in the reservoir to the release rate described above. This model assumes a solution of therapeutic agent where the concentration in the reservoir is substantially uniform. In addition, the concentration in the receiving fluid or vitreous is considered negligible (c_(V)=0). Solving the differential equation and rearrangement yields the following equations describing the concentration in the reservoir as a function of time, t, and volume of the reservoir, V_(R), for release of a therapeutic agent from a solution in a reservoir though a porous structure.

c _(R) =c _(R0)exp((−DPA/FLV _(R))t)

and

Cumulative Release=1−c _(R) /c _(R0)

When the reservoir contains a suspension, the concentration in reservoir, c_(R), is the dissolved concentration in equilibrium with the solid (i.e., the solubility of the therapeutic agent). In this case, the concentration in the reservoir is constant with time, the release rate is zero order, and the cumulative release increases linearly with time until the time when the solid is exhausted.

Therapeutic concentrations for many ophthalmic therapeutic agents may be determined experimentally by measuring concentrations in the vitreous humor that elicit a therapeutic effect. Therefore, there is value in extending predictions of release rates to predictions of concentrations in the vitreous. A one-compartment model may be used to describe elimination of therapeutic agent from eye tissue.

Current intravitreal administration of therapeutic agents such as Lucentis™ involves a bolus injection. A bolus injection into the vitreous may be modeled as a single exponential with rate constant, k=0.693/half-life and a cmax=dose/V, where V, is the vitreous volume. As an example, the half-life for ranibizumab is approximately 3 days in the rabbit and the monkey (Gaudreault et al) and 9 days in humans (Lucentis™ package insert). The vitreous volume is approximately 1.5 mL for the rabbit and monkey and 4.5 mL for the human eye. The model predicts an initial concentration of 333 ug/mL for a bolus injection of 0.5 mg Lucentis™ into the eye of a monkey. This concentration decays to a vitreous concentration of 0.1 ug/mL after about a month.

For devices with extended release, the concentration in the vitreous changes slowly with time. In this situation, a model can be derived from a mass balance equating the release rate from the device (described by equations above) with the elimination rate from the eye, k c_(v) V_(v). Rearrangement yields the following equation for the concentration in the vitreous: c_(v)=Release rate from device/k V_(v).

Since the release rate from a device with a solution of therapeutic agent decreases exponentially with time, the concentration in the vitreous decreases exponentially with the same rate constant. In other words, vitreous concentration decreases with a rate constant equal to D PA/FL V_(R) and, hence, is dependent on the properties of the porous structure and the volume of the reservoir.

Since the release rate is zero order from a device with a suspension of therapeutic agent, the vitreous concentration will also be time-independent. The release rate will depend on the properties of the porous structure via the ratio, PA/FL, but will be independent of the volume of the reservoir until the time at which the drug is exhausted.

The channels of the rigid porous structure can be sized in many ways to release the intended therapeutic agent. For example, the channels of the rigid porous structure can be sized to pass therapeutic agent comprising molecules having a molecular weight of at least about 100 Daltons or for example, at least about 50 k Daltons. The channels of the rigid porous structure can be sized to pass therapeutic agent comprising molecules comprising a cross-sectional size of no more than about 10 nm. The channels of the rigid porous structure comprise interconnecting channels configured to pass the therapeutic agent among the interconnecting channels. The rigid porous structure comprises grains of rigid material and wherein the interconnecting channels extend at least partially around the grains of rigid material to pass the therapeutic agent through the porous material. The grains of rigid material can be coupled together at a loci of attachment and wherein the interconnecting channels extend at least partially around the loci of attachment.

The porous structure and reservoir may be configured to release the glucocorticoid for an extended time of at least about six months with a therapeutic amount of glucocorticoid of corresponding to an in situ concentration within a range from about 0.05 ug/mL to about 4 ug/mL, for example from 0.1 ug/mL to about 4 ug/mL, so as to suppress inflammation in the retina-choroid.

The porous structure comprises a sintered material. The sintered material may comprise grains of material in which the grains comprise an average size of no more than about 20 um. For example, the sintered material may comprise grains of material in which the grains comprise an average size of no more than about 10 um, an average size of no more than about 5 um, or an average size of no more than about 1 um. The channels are sized to pass therapeutic quantities of the therapeutic agent through the sintered material for the extended time based on the grain size of the sintered material and processing parameters such as compaction force and time and temperature in the furnace. The channels can be sized to inhibit penetration of microbes including bacteria and fungal spores through the sintered material.

The sintered material comprises a wettable material to inhibit bubbles within the channels of the material.

The sintered material comprises at least one of a metal, a ceramic, a glass or a plastic. The sintered material may comprises a sintered composite material, and the composite material comprises two or more of the metal, the ceramic, the glass or the plastic. The metal comprises at least one of Ni, Ti, nitinol, stainless steel including alloys such as 304, 304L, 316 or 316L, cobalt chrome, elgiloy, hastealloy, c-276 alloy or Nickel 200 alloy. The sintered material may comprise a ceramic. The sintered material may comprise a glass. The plastic may comprise a wettable coating to inhibit bubble formation in the channels, and the plastic may comprise at least one of polyether ether ketone (PEEK), polyethylene, polypropylene, polyimide, polystyrene, polycarbonate, polyacrylate, polymethacrylate, or polyamide.

The rigid porous structure may comprise a plurality of rigid porous structures coupled to the reservoir and configured to release the therapeutic agent for the extended period. For example, additional rigid porous structure can be disposed along the container, for example the end of the container may comprise the porous structure, and an additional porous structure can be disposed along a distal portion of the container, for example along a tubular sidewall of the container.

The therapeutic device can be tuned to release therapeutic amounts of the therapeutic agent above the minimum inhibitory concentration for an extended time based on bolus injections of the therapeutic agent. For example, the volume of the chamber of the reservoir can be sized with the release rate of the porous structure based on the volume of the bolus injection. A formulation of a therapeutic agent can be provided, for example a known intravitreal injection formulation. The therapeutic agent can be capable of treating the eye with bolus injections, such that the formulation has a corresponding period between each of the bolus injections to treat the eye. For example the bolus injections may comprise monthly injections. Each of the bolus injections comprises a volume of the formulation, for example 50 uL. Each of the bolus injections of the therapeutic agent may correspond to a range of therapeutic concentrations of the therapeutic agent within the vitreous humor over the time course between injections, and the device can be tuned so as to release therapeutic amounts of the therapeutic agent such that the vitreous concentrations of the released therapeutic agent from the device are within the range of therapeutic concentrations of the corresponding bolus injections. For example, the therapeutic agent may comprise a minimum inhibitory concentration to treat the eye, for example at least about 3 ug/mL, and the values of the range of therapeutic concentrations can be at least about 3 ug/mL. The therapeutic device can be configured to treat the eye with an injection of the monthly volume of the formulation into the device, for example through the penetrable barrier. The reservoir of the container has a chamber to contain a volume of the therapeutic agent, for example 35 uL, and a mechanism to release the therapeutic agent from the chamber to the vitreous humor.

The volume of the container and the release mechanism can be tuned to treat the eye with the therapeutic agent with vitreous concentrations within the therapeutic range for an extended time with each injection of the quantity corresponding to the bolus injection, such that the concentration of the therapeutic agent within the vitreous humor remains within the range of therapeutic concentrations and comprises at least the minimum inhibitory concentration. The extended time may comprise at least about twice the corresponding period of the bolus injections. The release mechanism comprises one or more of a porous frit, a sintered porous fit, a permeable membrane, a semi-permeable membrane, a capillary tube or a tortuous channel, nano-structures, nano-channels or sintered nano-particles. For example, the porous frit may comprises a porosity, cross sectional area, and a thickness to release the therapeutic agent for the extended time. The volume of the container reservoir can be sized in many ways in relation to the volume of the injected formulation and can be larger than the volume of injected formulation, smaller than the volume of injected formulation, or substantially the same as the volume of injected formulation. For example, the volume of the container may comprise no more than the volume of the formulation, such that at least a portion of the formulation injected into the reservoir passes through the reservoir and comprises a bolus injection to treat the patient immediately. As the volume of the reservoir is increased, the amount of formulation released to the eye through the porous structure upon injection can decrease along with the concentration of active ingredient of the therapeutic agent within the reservoir, and the release rate index can be increased appropriately so as to provide therapeutic amounts of therapeutic agent for the extended time. For example, the volume of the reservoir of the container can be greater than the volume corresponding to the bolus injection, so as to provide therapeutic amounts for at least about five months, for example 6 months, with an injection volume corresponding to a monthly injection of Lucentis™. For example, the formulation may comprise commercially available Lucentis™, 50 uL, and the reservoir may comprise a volume of about 100 uL and provide therapeutic vitreous concentrations of at least about 3 ug/mL for six months with 50 uL of Lucentis™ injected into the reservoir.

The chamber may comprise a substantially fixed volume and the release rate mechanism comprises a substantially rigid structure to maintain release of the therapeutic agent above the minimum inhibitory concentration for the extended time with each injection of a plurality of injections.

A first portion of the injection may pass through the release mechanism and treat the patient when the formulation is injected, and a second portion of the formulation can be contained in the chamber when the formulation is injected.

FIG. 6B-1 shows interconnecting channels 156 extending from first side 150S1 to second side 150S2 of the porous structure as in FIG. 6B. The interconnecting channels 156 extend to a first opening 158A1, a second opening 158A2 and an Nth opening 158AN on the first side 150S1. The interconnecting channels 156 extend to a first opening 158B1, a second opening 158B2 and an Nth opening 158BN on the second side 150S2. Each of the openings of the plurality of channels on the first side is connected to each of the openings of plurality of channels on the second side, such that effective length traveled along the channels is greater than thickness 150T. The channel parameter can be within a range from about 1.1 to about 10, such that the effective length is within a range from about 1.1 to 10 times the thickness 150T. For example, the channel parameter can be about 1 and the porosity about 0.2, such that the effective length corresponds to at least about 5 times the thickness 150T.

FIG. 6B-2 shows a plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side 150S1 to a second side 15052 of the porous structure as in FIGS. 6B and 6B-1. The plurality of paths comprises a first path 156P1 extending from the first side to the second side, a second path 156P2 extending from the first side to the second side and a third path 156P3 extending from the first side to the second side, and many additional paths. The effect length of each of first path P1, second path P2 and third path P3 is substantially similar, such that each opening on the first side can release the therapeutic agent to each interconnected opening on the second side. The substantially similar path length can be related to the sintered grains of material and the channels that extend around the sintered material. The porous structure may comprise randomly oriented and connected grains of material, packed beads of material, or combinations thereof. The channel parameter can be related to the structure of the sintered grains of material and corresponding interconnecting channels, porosity of the material, and percolation threshold. Work in relation to embodiments shows that the percolation threshold of the sintered grains may be below the porosity of the porous frit structure, such that the channels are highly inter-connected. The sintered grains of material can provide interconnected channels, and the grains can be selected to provide desired porosity and channel parameters and RRI as described herein.

The channel parameter and effective length from the first side to the second side can be configured in many ways. The channel parameter can be greater than 1 and within a range from about 1.2 to about 5.0, such that the effective length is within a range about 1.2 to 5.0 times the thickness 150T, although the channel parameter may be greater than 5, for example within a range from about 1.2 to 10. For example, the channel parameter can be from about 1.3 to about 2.0, such that the effective length is about 1.3 to 2.0 times the thickness 150T. For example, experimental testing has shown the channel parameter can be from about 1.4 to about 1.8, such that the effective length is about 1.4 to 1.8 times the thickness 150T, for example about 1.6 times the thickness. These values correspond to the paths of the channels around the sintered grains of material, and may correspond, for example, to the paths of channels around packed beads of material.

FIG. 6B-3 shows blockage of the openings with a covering 156B and the plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side to a second side of the porous structure as in FIGS. 6B and 6B-1. A plurality of paths 156PR extend from the first side to the second side couple the first side to the second side where one of the sides is covered, such that the flow rate is maintained when one of the sides is partially covered.

FIG. 6B-4 shows blockage of the openings with particles 156PB and the plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side to a second side of the porous structure as in FIGS. 6B and 6B-1. The plurality of paths 156PR extend from the first side to the second side couple the first side to the second side where one of the sides is covered, such that the flow rate is maintained when one of the sides is partially covered

FIG. 6B-5 shows an effective cross-sectional size 150DE and area 150EFF corresponding to the plurality of paths of the therapeutic agent along the interconnecting channels extending from a first side to a second side of the porous structure as in FIGS. 6B and 6B-1. The effective cross sectional area of the interconnecting channels corresponds to the internal cross-sectional area of the porous structure disposed between the openings of the first side and the openings of the second side, such that the rate of release can be substantially maintained when the channels are blocked on the first side and the second side.

The rigid porous structure can be shaped and molded in many ways for example with tubular shapes, conical shapes, discs and hemispherical shapes. The rigid porous structure may comprise a molded rigid porous structure. The molded rigid porous structure may comprises at least one of a disk, a helix or a tube coupled to the reservoir and configured to release the therapeutic agent for the extended period.

FIG. 6C shows a rigid porous structure as in FIG. 6B incorporated into a scleral tack 601 as described in U.S. Pat. No. 5,466,233. The scleral tack comprises a head 602, a central portion 603 and a post 604. The post may comprise the reservoir 605 and the rigid porous structure 606 as described above. The porous structure may comprise a molded conical structure having a sharp tip configured for insertion into the patient. Alternatively or in combination, the tip may be rounded.

FIG. 6E, shows a plurality of rigid porous structures as in FIG. 6B incorporated with a drug delivery device for sustained release as described in U.S. Pat. No. 5,972,369. The therapeutic device comprises a reservoir 613 to contain the therapeutic agent and an impermeable and non-porous outer surface 614. The reservoir is coupled to a rigid, porous structure 615 that extends to a distal end 617. The rigid porous structure comprises an exposed area 616 on the distal end to release the therapeutic agent, and the impermeable and non-porous outer surface may extend to the distal end.

FIG. 6D shows a rigid porous structure as in FIG. 6B incorporated with a delivery device for sustained release as described in U.S. Pat. Pub. 2003/0014036 A 1. The drug delivery device comprises an inlet port 608 on the proximal end and a hollow body 609 coupled to the inlet port. The hollow body comprises many openings 612 that allow a solution injected into the inlet port to pass from the hollow body into a balloon 610. The balloon comprises a distal end 611 disposed opposite the injection port. The balloon comprises a plurality of the rigid porous structures 607, as described above. Each of the plurality of porous rigid structures comprises a first surface exposed to the interior of the balloon and a second surface configured to contact the vitreous. The calculated area can be the combined area of the plurality of porous rigid structures as noted above.

FIG. 6F shows a rigid porous structure as in FIG. 6B incorporated with a non-linear body member 618 for sustained release as described in U.S. Pat. No. 6,719,750. The non-linear member may comprise a helical shape. The non-linear member can be coupled to a cap 619 on the proximal end 620. The non-linear member may comprise a lumen 621 filled with therapeutic agent so as to comprise a reservoir 622. The porous structure 623 can be disposed on a distal end 624 of the non-linear member to release the therapeutic agent. The porous structure may be located at additional or alternative locations of the non-linear member. For example a plurality of porous structures may be disposed along the non-linear member at locations disposed between the cap and distal end so as to release therapeutic agent into the vitreous humor when the cap is positioned against the sclera.

FIG. 6G shows porous nanostructures, in accordance with embodiments. The porous structure 150 may comprise a plurality of elongate nano-channels 156NC extending from a first side 150S1 of the porous structure to a second side 150S2 of the porous structure. The porous structure 150 may comprise a rigid material having the holes formed thereon, and the holes may comprise a maximum dimension across such as a diameter. The diameter of the nano-channels may comprise a dimension across, for example from about 10 nm across, to about 1000 nm across, or larger. The channels may be formed with etching of the material, for example lithographic etching of the material. The channels may comprise substantially straight channels such that the channel parameter F comprises about 1, and the parameters area A, and thickness or length L correspond to the combined cross-sectional area of the channels and the thickness or length of the porous structure.

The porous structure 150 may comprise interconnecting nano-channels, for example formed with a sintered nano-material.

The injection of therapeutic agent into the device 100 as described herein can be performed before implantation into the eye or alternatively when the therapeutic device is implanted into the eye.

FIG. 7 shows a therapeutic device 100 coupled to an injector 701 that removes material from the device and injects therapeutic agent 702 into the device. The injector picks up spent media 703 and refills the injector with fresh therapeutic agent. The therapeutic agent is injected into the therapeutic device. The spent media is pulled up into the injector. The injector may comprise a stopper mechanism 704.

The injector 701 may comprise a first container 702C to contain a formulation of therapeutic agent 702 and a second container 703C to receive the spent media 703. Work in relation to embodiments suggests that the removal of spent media 703 comprising material from the container reservoir of the therapeutic device can remove particulate from the therapeutic device, for example particles comprised of aggregated therapeutic agent such as protein. The needle 189 may comprise a double lumen needle with a first lumen coupled to the first container and a second lumen coupled to the second container, such that spent media 703 passes from the container reservoir of device 100 to the injector. A valve 703V, for example a vent, can be disposed between the second lumen and the second container. When the valve is open and therapeutic agent is injected, spent media 703 from the container reservoir of the therapeutic device 100 passes to the second container of the injector, such that at least a portion of the spent media within the therapeutic device is exchanged with the formulation. When the valve is closed and the therapeutic agent is injected, a portion of the therapeutic agent passes from the reservoir of the therapeutic device into the eye. For example, a first portion of formulation of therapeutic agent can be injected into therapeutic device 100 when the valve is open such that the first portion of the formulation is exchanged with material disposed within the reservoir; the valve is then closed and a second portion of the formulation is injected into therapeutic device 100 such that at least a portion of the first portion passes through the porous structure into the eye. Alternatively or in combination, a portion of the second portion of injected formulation may pass through the porous structure when the second portion is injected into the eye. The second portion of formulation injected when the valve is closed may correspond to a volume of formulation that passes through the porous structure into the vitreous humor to treat the patient immediately.

The needle 189 may comprise a dual lumen needle, for example.

FIG. 7A shows a therapeutic device having a reservoir 140 tuned to receive an injection of a first amount of first therapeutic agent 110A and a second amount of second therapeutic agent 110B. The first amount of first therapeutic agent 110A and the second amount of second therapeutic agent 110B can be mixed together and injected from injector 187. Reservoir 140 comprises container 130 having chamber 132 coupled to porous structure 150. The container can be tuned with the volume and RRI of the porous structure to receive the first amount of first therapeutic agent 110A and second amount of second therapeutic agent 110B injected into chamber 132 with the first amount. Based on the teachings described herein a person of ordinary skill in the art can conduct experiments and simulations to determine the release rate index, volume of the chamber, the first amount and the second amount so as to release the first therapeutic agent 110A for a first extended time and the second therapeutic agent 110B for a second extended time.

FIG. 7A-1 shows a therapeutic device 100 comprising a penetrable barrier coupled to an injector needle 189 comprising a stop 189S that positions the distal end of the needle near the proximal end of the reservoir 130 of the device to flush the reservoir with ejection of liquid formulation through the porous fit structure, in accordance with embodiments. For example, the injector needle may comprise a single lumen needle having a bevel that extends approximately 0.5 mm along the shaft of the needle from the tip of the needle to the annular portion of the needle. The stop can be sized and positioned along an axis of the needle such that the needle tip extends a stop distance 189SD into the reservoir as defined by the length of the needle from the stop to the tip and the thickness of the penetrable barrier, in which the stop distance is within a range from about 0.5 to about 2 mm. The reservoir may extend along an axis of the therapeutic device distance within a range from about 4 to 8 mm. A volume comprising a quantity of liquid formulation within a range from about 20 to about 200 uL, for example about 50 uL can be injected into the therapeutic device with the needle tip disposed on the distal end. The volume of the reservoir can be less than the injection volume of the formulation of therapeutic agent, such that liquid is flushed through the porous structure 150. For example, the reservoir may comprise a volume within a range from about 20 to 40 uL, and the injection volume of the liquid formulation of therapeutic agent may comprise about 40 to 100 uL, for example about 50 uL.

FIG. 7A-2 shows a therapeutic device comprising a penetrable barrier coupled to a needle 189 of an injector 701 to inject and remove material from the device such that the liquid in the reservoir 130 is exchanged with the injected formulation. The needle comprises at least one lumen and may comprise a concentric double lumen needle 189DL with a distal end coupled to the inner lumen to inject formulation of the therapeutic agent into the therapeutic device and a proximal vent 189V to receive liquid into the needle when the formulation is injected. Alternatively, the vent may correspond to an opening on the distal end of the inner lumen of the needle and the outer lumen may comprise a proximal opening to inject therapeutic agent formulation into a proximal portion of the container reservoir.

Work in relation to the injector embodiments indicates that a filling efficiency of at least about 80%, for example 90% or more can be achieved with injector apparatus and needles as described above.

FIG. 7B-1 shows a side cross-sectional view of therapeutic device 100 comprising a retention structure having a cross-section sized to fit in an elongate incision. The retention structure shown can be combined with one or more therapeutic agents as described herein. For example, the volume and RRI can be tuned to receive a quantity of the first therapeutic agent by injection, and the second therapeutic agent 110B may comprise a solid located in the chamber 132. The release rate index and volume of chamber 132 can be sized to receive a quantity of first therapeutic agent 110A. The release rate index can be sized to release therapeutic amounts of the second therapeutic agent 110B for a second extended time. Based on the teachings described herein a person of ordinary skill in the art can conduct experiments and simulations to determine the release rate index, volume of the chamber, the first amount and the second amount so as to release the first therapeutic agent 110A for a first extended time and the second therapeutic agent 110B for a second extended time through the porous structure 150.

The cross-section sized to fit in the elongate incision may comprise a narrow portion 120N of retention structure 120 that is sized smaller than the flange 122. The narrow portion 120N sized to fit in the elongate incision may comprise an elongate cross section 120NE sized to fit in the incision. The narrow portion 120N may comprise a cross-section having a first cross-sectional distance across, or first dimensional width, and a second cross-sectional distance across, or second dimensional width, in which the first cross-sectional distance across is greater than the second cross-sectional distance across such that the narrow portion 120N comprises an elongate cross-sectional profile.

The elongate cross section 120NE of the narrow portion 120N can be sized in many ways to fit the incision. The elongate cross section 120NE comprises a first dimension longer than a second dimension and may comprise one or more of many shapes such as dilated slot, dilated slit, lentoid, oval, ovoid, or elliptical. The dilated slit shape and dilated slot shape may correspond to the shape sclera tissue assumes when cut and dilated. The lentoid shape may correspond to a biconvex lens shape. The elongate cross-section of the narrow portion may comprise a first curve along an first axis and a second curve along a second axis different than the first curve.

Similar to the narrow portion 120N of the retention structure, the container reservoir may comprise a cross-sectional profile.

FIG. 7B-2 shows an isometric view of the therapeutic device as in FIG. 7B-1.

FIG. 7B-3 shows a top view of the therapeutic device as in FIG. 7B-1.

FIG. 7B-4 shows a side cross sectional view along the short side of the retention structure of the therapeutic device as in FIG. 7B-1.

FIG. 7B-5 shows a bottom view of the therapeutic device as in FIG. 7B-1 implanted in the sclera.

FIG. 7B-5A shows a cutting tool 710 comprising a blade 714 having a width 712 corresponding to perimeter 160P of the barrier 160 and the perimeter 160NP of the narrow portion. The cutting tool can be sized to the narrow portion 120N so as to seal the incision with the narrow portion when the narrow portion is positioned against the sclera. For example, the width 712 may comprise about one half of the perimeter 160P of the barrier 160 and about one half of the perimeter 160NP of the narrow portion 160N. For example, the outside diameter of the tube of barrier 160 may comprise about 3 mm such that the perimeter of 160P comprises about 6 mm, and the narrow portion perimeter 160NP may comprise about 6 mm. The width 712 of the blade 710 may comprise about 3 mm such that the incision comprises an opening having a perimeter of about 6 mm so as to seal the incision with the narrow portion 160P. Alternatively, perimeter 160P of barrier 160 may comprise a size slightly larger than the incision and the perimeter of the narrow portion.

The retention structure comprises a narrow section 120N having a short distance 120NS and a long distance 120NL so as to fit in an elongate incision along the pars plana of the eye. The retention structure comprises an extension 122. The extension of the retention structure 120E comprises a short distance across 122S and a long distance across 122S, aligned with the short distance 122NS and long distance 122NL of the narrow portion 120N of the retention structure 120. The narrow portion 120 may comprise an indentation 1201 sized to receive the sclera.

FIGS. 8A and 8A1 show a side cross sectional view and a top view, respectively, of therapeutic device 100 for placement substantially between the conjunctiva and the sclera. The therapeutic agent 110 as described herein can be injected when device 100 is implanted. The therapeutic device 100 comprises container 130 as described herein having penetrable barrier 184 as described herein disposed on an upper surface for placement against the conjunctiva. An elongate structure 172 is coupled to container 130. Elongate structure 172 comprises a channel 174 extending from a first opening coupled to the chamber of the container to a second opening 176 on a distal end of the elongate structure. The porous structure 150 as described herein is located on the elongate structure 172 and coupled to the container 130 so as to release therapeutic agent for an extended period, and a retention structure 120 comprising an extension protruding outward from the container 130 to couple to the sclera and the conjunctiva. The container may comprise barrier 160 as described herein that defines at least a portion of the reservoir, and the container may comprise a width, for example a diameter. The barrier 160 may comprise a rigid material, for example rigid silicone or rigid rubber, or other material as described herein, such that the volume of the chamber of container 130 comprises a substantially constant volume as described herein. Alternatively or in combination, barrier 160 may comprise a soft material, for example when the chamber size is decreased such that the volume can be substantially constant with the decreased chamber size. A soft barrier material can be combined with a rigid material, for example a support material. The diameter can be sized within a range, for example within a range from about 1 to about 8 mm, for example within a range from about 2 to 6 mm and can be about 3 mm, for example.

The container may be coupled to elongate structure 172 sized, and the elongate structure having a length sized so as to extend from the conjunctive to the vitreous to release the therapeutic agent into the vitreous. The length can be sized within a range, for example within a range from about 2 to about 14 mm, for example within a range from about 4 to 10 mm and can be about 7 mm, for example. The penetrable barrier may comprise a septum disposed on a proximal end of the container, in which the septum comprises a barrier that can be penetrated with a sharp object such as a needle for injection of the therapeutic agent. The porous structure may comprise a cross sectional area sized to release the therapeutic agent for the extended period. The elongate structure 172 can be located near a center of the container 130, or may be eccentric to the center.

The elongate structure 172 can be inserted into the sclera at the pars plana region as described herein.

The barrier 160 can have a shape profile for placement between the conjunctiva and sclera. The lower surface can be shaped to contact the sclera and may comprise a concave shape such as a concave spherical or toric surface. The upper surface can be shaped to contact the conjunctivae and may comprise a convex shape such as a convex spherical or toric surface. The barrier 160 may comprise an oval, an elliptical, or a circular shape when implanted and viewed from above, and the elongate structure 172 can be centered or eccentric to the ellipse. When implanted the long dimension of the oval can be aligned so as to extend along a circumference of the pars plana.

The cross sectional diameter of the elongate structure 172 can be sized to decrease the invasiveness of device 100, and may comprise a diameter of no more than about 1 mm, for example no more than about 0.5 mm, for example no more than about 0.25 mm such that the penetrate sclera seals substantially when elongate structure 172 is removed and the eye can seal itself upon removal of elongate structure 172. The elongate structure 172 may comprise a needle, and channel 174 may comprise a lumen of the needle, for example a 30 Gauge needle.

The porous structure 150 may comprise a first side a described herein coupled to the reservoir and a second side to couple to the vitreous. The first side may comprise a first area 150 as described herein and the second side may comprise a second area. The porous structure may comprise a thickness as described herein. The porous structure many comprise a diameter. The porous structure may comprise a release rate index, and the chamber of container 130 that defines the volume of reservoir 140 can be sized such that the porous structure and the volume are tuned to receive and amount of therapeutic agent injected with a volume of formulation of therapeutic agent and tuned to release therapeutic amounts for an extended time. Many release rate mechanisms as described herein can be used to tune the release rate and volume to the quantity of therapeutic agent injected as described herein.

The volume of the reservoir 140 defined by the chamber of the container may comprise from about 5 uL to about 2000 uL of therapeutic agent, or for example from about 10 uL to about 200 uL of therapeutic agent.

The porous structure may comprise a needle stop that limits penetration of the needle. The porous structure may comprise a plurality of channels configured for the extended release of the therapeutic agent. The porous structure may comprise a rigid sintered material having characteristics suitable for the sustained release of the material.

FIG. 8A2 shows the therapeutic device 100 implanted with the reservoir between the conjunctiva and the scleara, such that elongate structure 172 extends through the sclera to couple the reservoir chamber to the vitreous humor. When implanted, the porous structure 150 can be located in the viteous humor, or located between the conjunctiva and sclera, or may extend through the sclera, or combinations thereof.

FIG. 9 shows the porous structure 150 of therapeutic device 100 located in channel 174 near the opening to the chamber of the container 130. The porous structure can extend substantially along the length of elongate structure 172.

FIG. 10 shows the porous structure 150 located within the chamber of container 150 and coupled to the first opening of the elongate structure 172 so as to provide the release rate profile. The porous structure can cover the opening of elongate structure 172 such that therapeutic amounts are released for the extended time as described herein.

FIG. 11 shows a plurality of injection ports spaced apart so as to inject and exchange the liquid of chamber of the container 130 and inject the therapeutic agent into the reservoir chamber of the container 130. The penetrable barrier 184 may comprise a first penetrable barrier located in a first access port formed in the barrier 160 and a second penetrable barrier located in a second access port formed in the barrier 160, and the first barrier can be separated from the second barrier by at least about 1 mm.

The injector 701 as described above can be configured to coupled to the reservoir placed between the conjunctiva and the sclera as describe herein. The injector 701 can be coupled to a double lumen needle 189L such that a second lumen 189B injects therapeutic agent 110 from a chamber 702C into device 100, and the first lumen can be spaced apart from the second lumen with the distance extending therebetween sized to position the first lumen in the first septum as described above and the second lumen in the second septum as described above. The second container 703C can be coupled to a first lumen 189A that extends to the chamber of the reservoir container and receives liquid from device 100, such that liquid of device 100 is exchanged when the chamber of the reservoir container is positioned between the conjunctiva and the sclera. The switching valve 703V to exchange an intended amount of liquid and an intended amount of the formulation the therapeutic agent 110, and inject an intended amount of therapeutic agent injected into device 100, for example such that a bolus amount of therapeutic agent can be injected from device 100 as described above. A portion of the formulation of therapeutic agent injected into device 100 can be retained in device 100 for release for an extended time.

The injector 701 can be used to exchange a liquid comprising a first therapeutic agent such as an antineoplastic agent, for example a VEGF inhibitor, and a second therapeutic agent such as a COX inhibitor, for example the ketorolac, such that the first and second therapeutic agent are injected together and exchanged with a liquid in the reservoir. The reservoir can be located between the sclera and the conjunctiva, or within the vitreous, or combinations thereof.

FIG. 12 shows the elongate structure 172 coupled to the container 130 away from the center of container 130 and near and located near an end of the container.

The first therapeutic device may comprise a device having the reservoir located in the vitreous humor and the second therapeutic device may comprise a device having the reservoir located between the conjunctiva and the sclera, in accordance with embodiments as described herein.

The following examples are provided as non-limiting examples in accordance with embodiments of the present invention as described herein.

Example A Combined Treatment with a First Anti-Neoplasia Therapeutic Agent and a Second Antiinflammatory Therapeutic Agent

A first therapeutic agent comprising an anti-neoplasia agent, such as an antineovascular agent, for example a VEGF inhibitor such as a Lucentis can be combined with an antiinflammatory, such as steroid comprising triamcinolone actendie. The release of triamcinolone acetonide suspension is described supra in Examples 10 and 11 and corresponding FIG. 20. The first reservoir may comprise a volume of about 125 uL and an RRI of about 0.1 such that the first reservoir is tuned to receive a 50 uL injection of Lucentis and provide a concentration of about 3 ug/mL in the vitreous humor. The second reservoir may comprise Triamcinolone Acetonide having an RRI of 1.2, as described in Example 11, supra. The second reservoir may be configured in parallel or in series as described herein, and provide trimcinolone acetonide for about 400 days over the course of at least 2 sequential 50 uL injections of Lucentis at day 0 and day 180, for example.

The amount of triamcinolone acetate suspension in the second chamber can be may be increased so as to comprise about a 20 uL reservoir volume loaded with 0.8 mg using a commercial drug product (40 mg/mL triamcinolone acetonide), such that the trimcinolone acetonide can be delivered in therapeutic amounts for an extended time of at least about 800 days, corresponding to about four sequential 50 uL injections of Lucentis™ at six month intervals. The IC50 of triamcinolone can be about 1.5 nM, depending on the target assay such as such as one or more of VEGF-induced cell proliferation, or receptor binding.

The amount of Ranibizumab in the first chamber can be agent may be increased, for example to about 2.5 mg, for example, such that the amount Ranibizumab delivered in therapeutic amounts for an extended time, and the RRI can be adjusted accordingly for example the RRI can be about 0.02 and provide about 10 ug/mL of Ranibizumab at about 6 months.

Example B VEGF Inhibitors Combined with COX Inhibitors

A first therapeutic agent comprising an anti-neoplasia agent, such as an antineovascular agent, for example a VEGF inhibitor such as a Lucentis can be combined with a non-steroidal antiinflammatory, such as a COX inhibitor, for example comprising celecoxib. The release of the small molecule cyclcoxib through the porous frit structure 150 can be similar to triamcinolone acetonide as described supra in Examples 10 and 11 and corresponding FIG. 20. The first reservoir may comprise a volume of about 125 uL and an RRI of about 0.1 such that the first reservoir is tuned to receive a 50 uL injection of Lucentis and provide a concentration of about 3 ug/mL in the vitreous humor. The second reservoir may comprise solid celecoxib and have an RRI of 1.2, similar to that described in Example 11, supra. The second reservoir may be configured in parallel or in series as described herein, and provide therapeutic amounts of celecoxib.

The amount of celecoxib solid in the second chamber can be may be increased so as to provide therapeutic amounts of celecoxib for the extended time. Based on the teachings described herein a person of ordinary skill in the art can determine the concentration of cycloscoxib in the vitreous humor to achieve therapeutic inhibition of COX for the treatment of one or more stages of AMD, and the RRI, reservoir volume and amount of solid can be determined. The IC50 of cyclcoxib can be approximately 40 nM, about 40 times less potent than triamcinolone acetonide. The celecoxib can be released from a separate chamber, for example from a separate device, and the amount of celecoxib solid released from the separate device may comprise about 20 mg released over about 200 days, for example.

TABLE 3A Examples of COX Inhibitors combined with the VEGF inhibitor Ranibizumab Therapeutic Delivery Device Parameters celecoxib ketorolac bromfenac RRI 3 0.02 5 volume(ul)/conc (mg/ml) 10/50 25/175 10/50 Constant delivery (days) 500 180 178 Vitreous concentration 0.13 0.9 0.1 (ug/ml) IC50 (ug/ml) (Inhibitory 0.015 0.007 0.0025 Level)* Table 3A shows examples of COX inhibitors that can be injected into the therapeutic device. The COX inhibitor may comprise celecoxib, keotolac or bromefenac. The RRIs, volumes and concentrations are shown to release therapeutic amounts for the times indicated time, and the vitreous concentrations are shown above the IC 50 concentrations.

TABLE 3B Coefficients to determine ketorolac release rate profile. Diffusion coeff (cm2/s) 5.0E−06 Solubility (ug/mL) 25000 Reservoir Vol (ml) 0.0250 PA/FL (RRI, mm) 0.02 Half-life (hr) 3 Rate constant, k (1/day) 5.545 Vitreous vol (ml) 4.5

TABLE 3C Loading of Ketorolac to provide 318 days with a release rate of 21.6 ug/day and a vitreous concentration of 0.9 ug/mL Diffusion coeff (cm2/s) 5.0E−06 Loading (mg/mL) 300.0 Solubility (mg/mL) 25.00 Reservoir Vol (ml) 0.025 Half-life (hr) 3 Rate constant, k (1/day) 5.545 Vitreous vol (ml) 4.5

TABLE 3D Steady state release rate profile of Ketorolac suspension for 180 days. Constant Rate Predicted Predicted Delivery Vitreous PA/TL Rate Time Conc (mm) (ug/day) (days) (ug/mL) 0.02 21.6 318 0.9

TABLE 3E Ketorolac release profiles when injected Ketorolac comprises a solution. Predicted Predicted Vitreous Time Rate Predicted Conc (days) (ug/day) % CR (ug/mL) 0 21.6 0.0% 0.866 0.0833333 21.5 0.3% 0.863 0.1666667 21.5 0.6% 0.861 0.25 21.4 0.9% 0.858 0.3333333 21.4 1.1% 0.856 0.4166667 21.3 1.4% 0.853 0.5 21.2 1.7% 0.851 0.5833333 21.2 2.0% 0.848 0.6666667 21.1 2.3% 0.846 0.75 21.0 2.6% 0.843 0.8333333 21.0 2.8% 0.841 0.9166667 20.9 3.1% 0.839 1 20.9 3.4% 0.836 10 15.3 29.2% 0.613 20 10.8 49.9% 0.434 30 7.7 64.5% 0.307 40 5.4 74.9% 0.217 50 3.8 82.2% 0.154 60 2.7 87.4% 0.109 70 1.9 91.1% 0.077 80 1.4 93.7% 0.055 90 1.0 95.5% 0.039 100 0.7 96.8% 0.027 110 0.5 97.8% 0.019 120 0.3 98.4% 0.014 130 0.2 98.9% 0.010 140 0.2 99.2% 0.007

Based on the above tables, Ketorolac has an initial steady state release rate profile from the suspension for 318 days with a vitreous concentration of about 0.9 ug/mL, followed by release of the remaining Ketorolac solution for about 70 days above about 0.07 ug/mL, for a total time above 0.07 of about 400 days. Based on the teachings described herein a person of ordinary skill in the art can determine many COX inhibitors suitable for release through the release mechanism with the antineoplastic agent such as the VEGF inhibitor, for example Lucentis.

The COX inhibitor can be combined with the VEGF inhibitor in the chamber of the therapeutic device and released together through the porous frit structure. The RRI of 0.02 shown for ketolac can be used with ranibizumab as described above, such that therapeutic amounts can be delivered for at least about 120 days, for example at least about 180 days. For example, the formulation may comprise Ranibizumab and ketorolac injected together into the therapeutic device. The values of RRI's and concentrations of Ranibizumab and volumes as described above are suitable for combination with a ketorolac suspension. The concentration of Ranibizumab in the formulation can be within the range from about 10 mg/ml to the upper limit of stable solubility of about 300 to 350 mg/mL. Additional VEGF inhibitors and COX inhibitors suitable for combination can be determined by one of ordinary skill in the art based on the teachings described herein.

Based on the teachings described herein, the vitreous half-life (clearance rate of the drug from the eye) is something that can be empirically determined. One of ordinary skill in the art could determine based upon similar MW to triamcinolone (celecoxib 381 vs. triamcinolone acetonide 394) and initially estimate the parameters to be the substantially same.

The IC50 can be defined as the concentration of drug which leads to a 50% inhibition in a particular assay. For celecoxib, the IC50 is approximately 15 ng/ml, corresponding to the minimum inhibitory concentration desired in the target tissue (retina, choroid). As a rough approximation, one could target above this concentration in the vitreous. The solubility of celecoxib in water is approximately 3 ug/ml, so is this relatively “water insoluble” The solubility of triamcinolone acetonide is about 19 ug/mL measured at 37° C. in 0.2 M potassium chloride and the diffusion coefficient of 5 e-6 cm²/s representative of a small molecule. The RRI for celecoxib can be about 600× the RRI for triamcinolone acetonide based on the above solubility and IC 50 data, for example an RRI of about 60.

Many amounts of Ranibizumab can be used, for example within a range from about 0.5 mg to about 10 mg, for example from about 1 mg to about 5 mg, for example from about 1.5 mg to about 3 mg, and the reservoir volume and release rate index can be sized based on the teaching described herein to proved the sustained release for the extended time. The amount of Ranibizumab in the chamber can be about 2 mg, for example, such that the amount Ranibizumab delivered in therapeutic amounts for an extended time, and the RRI can be adjusted accordingly for example the RRI can be about 0.02 and provide about 10 ug/mL of Ranibizumab at least about 6 months.

EXPERIMENTAL

Examples 1-4 (along with Examples 5-17C) are described in priority U.S. Provisional Pat. App. Ser. No. 61/371,168, filed 5 Aug. 2010; U.S. application Ser. No. 12/696,678, filed Jan. 29, 2010, entitled “Posterior Segment Drug Delivery”, published as U.S. Pat. App. Pub. No. 2010/0255061 (attorney docket not. 026322-003750US); and PCT/US2010/022631, published 5 Aug. 2010 as WO2010/088548, entitled “Posterior Segment Drug Delivery”.

Example 5 Release of Protein Through a Cylindrical Sintered Porous Titanium Cylinder

Reservoirs were fabricated from syringes and sintered porous titanium cylinders (available from Applied Porous Technologies, Inc., Mott Corporation or Chand Eisenmann Metallurgical). These were sintered porous cylinders with a diameter of 0.062 inches and a thickness of 0.039 inches prepared from titanium particles. The porosity is 0.17 with mean pore sizes on the order of 3 to 5 micrometers. The porous cylinder is characterized as 0.2 media grade according to measurements of bubble point. The porous cylinders were press-fit into sleeves machined from Delrin. The sleeves exposed one entire planar face to the solution in the reservoir and the other entire planar face to the receiver solution in the vials, corresponding to an area of 1.9 square millimeters. The tips were cut off of 1 mL polypropylene syringes and machined to accept a polymer sleeve with outer diameter slightly larger than the inner diameter of the syringe. The porous cylinder/sleeve was press-fit into the modified syringe.

A solution was prepared containing 300 mg/mL bovine serum albumin (BSA, Sigma, A2153-00G) in phosphate buffered saline (PBS, Sigma, P3813). Solution was introduced into the syringes by removing the piston and dispensing approximately 200 microliters into the syringe barrel. Bubbles were tapped to the top and air was expressed out through the porous cylinder. Then BSA solution was expressed through the porous cylinder until the syringe held 100 uL as indicated by the markings on the syringe. The expressed BSA solution was wiped off and then rinsed by submerging in PBS. The reservoirs were then placed into 4 mL vials containing 2 mL PBS at room temperature. Collars cut from silicone tubing were placed around the syringe barrels to position the top of the reservoir to match the height of PBS. The silicone tubing fit inside the vials and also served as a stopper to avoid evaporation. At periodic intervals, the reservoirs were moved to new vials containing PBS. The amount of BSA transported from the reservoir through the porous cylinder was determined by measuring the amount of BSA in the vials using a BCA™ Protein Assay kit (Pierce, 23227).

FIG. 13 shows the measured cumulative release of BSA through a sintered porous titanium disc and a prediction from the model describing release through a porous body. The Channel Parameter of 1.7 was determined via a least squares fit between the measured data and the model (MicroSoft Excel). Since the porous cylinder has equal areas exposed to the reservoir and receiving solution, the Channel Parameter suggests a tortuosity of 1.7 for porous titanium cylinders prepared from 0.2 media grade.

FIG. 13-1 shows the measured cumulative release of BSA of FIG. 13 measured to 180 days. The Channel Parameter of 1.6 was determined via a least squares fit between the measured data and the model (MicroSoft Excel). This corresponds to a Release Rate Index of 0.21 mm. Since the porous cylinder has equal areas exposed to the reservoir and receiving solution, the Channel Parameter corresponds to an effective path length channel parameter of 1.6 and suggests a tortuosity of 1.6 for porous titanium cylinders prepared from 0.2 media grade.

Example 6 Release of Protein Through Masked Sintered Porous Titanium Cylinders

Reservoirs were fabricated from syringes and porous sintered titanium cylinders similar to that described in Example 5. The porous sintered titanium cylinders (available from Applied Porous Technologies, Inc., Mott Corporation or Chand Eisenmann Metallurgical) had a diameter of 0.082 inch, a thickness of 0.039 inch, a media grade of 0.2 and were prepared from titanium particles. The porosity is 0.17 with mean pore sizes on the order of 3 to 5 micrometers. The porous cylinder is characterized as 0.2 media grade according to measurements of bubble point. The porous cylinders were press fit into sleeves machined from Delrin. The sleeves exposed one entire planar face to the solution in the reservoir and the other entire planar face to the receiver solution in the vials, corresponding to an area of 3.4 square millimeters. The tips were cut off of 1 mL polycarbonate syringes and machined to accept a polymer sleeve with outer diameter slightly larger than the inner diameter of the syringe. The porous cylinder/sleeve was press fit into the modified syringe. A kapton film with adhesive was affixed to the surface exposed to the receiving solution to create a mask and decrease the exposed area. In the first case, the diameter of the mask was 0.062 inches, exposing an area of 1.9 square millimeters to the receiving solution. In a second case, the diameter of the mask was 0.027 inches, exposing an area of 0.37 square millimeters.

Three conditions were run in this study: 1) 0.062 inch diameter mask, 100 uL donor volume, at room temperature in order to compare with reservoirs with unmasked porous cylinders in Example 5; 2) 0.062 inch diameter mask, 60 uL donor volume, at 37° C.; and 3) 0.027 inch diameter mask, 60 uL donor volume, at 37° C. The syringes were filled with a solution containing 300 mg/mL bovine serum albumin (BSA, Sigma, A2153-00G) in phosphate buffered saline (Sigma, P3813), similar to Example 5. In addition, 0.02 wt % of sodium azide (Sigma, 438456-5G) was added as a preservative to both the BSA solution placed in the reservoirs and the PBS placed in the receiving vials and both solutions were filtered through a 0.2 micron filter. This time, the amount of BSA solution dispensed into the syringe was weighed and the amount expressed through the porous cylinder was determined by rinsing and measuring the amount of BSA in the rinse. Assuming unit density for the BSA solution, the amount dispensed was 113+/−2 uL (Condition 1) and 66+/−3 uL (Condition 2). Subtracting off the amount in the rinse yielded a final reservoir volume of 103+/−5 uL (Condition 1) and 58+/−2 uL (Condition 2). The reservoirs were then placed into 5 mL vials containing 1 mL PBS at 37° C. in a heating block. At periodic intervals, the reservoirs were moved to new vials containing PBS and the BSA concentrations were determined in the receiving solutions using the method described in Example 5.

FIG. 14 shows the cumulative release of BSA protein through a masked sintered porous Titanium disc at Condition 1 (0.062 inch diameter mask, 100 uL donor volume, at room temperature) is faster than the release through an unmasked porous cylinder with the same exposed area (data from Example 5). Predictions are also shown using the Channel Parameter of 1.7 determined in Example 5, BSA diffusion coefficient at 20° C. (6.1e-7 cm²/s), reservoir volume of 100 uL, and the area of the porous cylinder exposed to the receiver solution (A=1.9 mm²) or the area of the porous cylinder exposed to the reservoir (A=3.4 mm²). The data for the masked porous cylinder matches more closely with larger area exposed to the reservoir. Hence, this mask with width of 0.7 mm is not sufficient to reduce the effective area of the porous cylinder for the dimensions of this porous cylinder.

FIG. 15 shows the cumulative release of BSA protein through a masked sintered porous titanium cylinder at Condition 2 (0.062 inch diameter mask, 60 uL donor volume, at 37° C.). The figure also displays predictions using the Channel Parameter of 1.7 determined in Example 5, BSA diffusion coefficient at 37° C. (9.1 e-7 cm²/s), reservoir volume of 58 uL, and the area of the porous cylinder exposed to the receiver solution (A=1.9 mm²) or the area of the porous cylinder exposed to the reservoir (A=3.4 mm²). Again, the data for this masked porous cylinder matches more closely with larger area exposed to the reservoir. The consistency of the data with the model at two temperatures supports how the model incorporates the effect of temperature.

FIG. 16 shows the cumulative release of BSA protein through a masked sintered porous titanium cylinder at Condition 3 (0.027 inch diameter mask, 60 uL donor volume, at 37° C.). The figure also displays predictions using the Channel Parameter of 1.7 determined in Example 5, BSA diffusion coefficient at 37° C. (9.1 e-7 cm²/s), reservoir volume of 58 uL, and the area of the porous cylinder exposed to the receiver solution (A=0.37 mm²) or the area of the porous cylinder exposed to the reservoir (A=3.4 mm²). This mask achieves a release rate corresponding to an effective area in between the area exposed to the reservoir and the area exposed to the receiver solution. A combination of the results in FIGS. 15 and 16 demonstrate that slower release is achieved using a mask that exposes a smaller area to the receiver solution.

FIGS. 13-16 show an unexpected result. Masking of the area of the porous fit structure so as to decrease the exposed area of the porous structure decreased the release rate less than the corresponding change in area. The release rate through the porous structure corresponds substantially to the interconnecting channels of the porous frit structure disposed between the first side exposed to the reservoir and the second side exposed to the receiver solution, such that the rate of release is maintained when a portion of the porous frit structure is covered. The rate of release of the interconnecting channels corresponds substantially to an effective area of the porous frit structure, and the effective area may correspond to an effective area of the interconnecting channels within the porous structure as shown above. As the rate of release is dependent upon the interconnecting channels, the release rate can be maintained when at least some of the channels are blocked, for example with coverage of a portion of the porous structure or blocking of a portion of the interconnecting channels with particles.

Example 7 Release of Protein Through Sintered Porous Stainless Steel Cylinder (Media Grade 0.1)

Prototype devices were fabricated from tubing and sintered porous stainless steel cylinders (available from Applied Porous Technologies, Inc., Mott Corporation or Chand Eisenmann Metallurgical) which are cylindrical with diameter 0.155 inch and thickness 0.188 inch prepared from 316L stainless steel particles. The porous cylinder is characterized as 0.1 media grade according to measurements of bubble point. This study was performed with these large, off-the-shelf porous cylinders with an area of 12 mm² in order to characterize the resistive properties of 0.1 media grade stainless steel.

These devices were prepared using Teflon-FEP heat shrink tubing (Zeus, #37950) and a hot air gun to shrink around the porous cylinders on one end and a custom prepared septum on the other end (Nusil MED1 4013 silicone molded to 0.145 inch diameter). The reservoir volume (46+/−2 uL) was determined from the difference in weight between empty systems and systems loaded with PBS. The PBS was loaded by submerging the systems in PBS and drawing a vacuum. The systems were then sterilized by heating to 250° F., 15 psi for 15 minutes, submerged in PBS in microcentrifuge tubes placed in a pressure cooker (Deni, 9760). Two 30G needles were inserted into the septum to displace the PBS with BSA solution. One was used to inject the BSA solution and the other was bent and used as a vent for the displaced PBS. Sufficient BSA solution was injected to fill the needle hub of the vent to approximately ¾ full. Similar to Example 6, the BSA and PBS contained sodium azide and the nominal concentration was 300 mg/mL BSA. The devices were placed into 1.5 mL microcentrifuge tubes containing 1 mL PBS and kept at 37° C. in a heating block. Pieces of silicone tubing (tight fit with inside of tube, hole for septum) were used to suspend the devices in the PBS with the bottom of the septum approximately the same height as the PBS. The concentrations in the first tubes contained BSA from the filling process and were discarded. At periodic intervals, the devices were moved to new tubes containing PBS and the BSA concentrations were determined in the receiving solutions using the method described in Example 5.

FIG. 17 displays the measured cumulative release of BSA through the 0.1 media grade stainless steel sintered titanium discs. Since the Porosity, P, is not available from the vendor at this time, a single parameter of Porosity divided by Channel Parameter was determined by least squares fit of the model to the data. Since the sintered porous structure is cylindrical, the Channel Parameter can be interpreted as the Tortuosity, T, and P/T was determined to be equal to 0.07.

Example 8 Release of Protein Through a Sintered Porous Stainless Steel Cylinder (Media Grade 0.2)

Prototype devices were fabricated from tubing and sintered porous stainless steel cylinders (available from Applied Porous Technologies, Inc., Mott Corporation or Chand Eisenmann Metallurgical) which are cylindrical with diameter 0.031 inch, and thickness 0.049 inch prepared from 316L stainless steel particles. The porous cylinder is characterized as 0.2 media grade according to measurements of bubble point. This porous cylinder was obtained as a custom order with properties determined from a previous study with a large diameter 0.2 media grade porous stainless steel cylinder (data no shown) and predictions based on the model described herein. The area of each face of this porous cylinder is 0.5 mm².

These devices were prepared using Teflon-FEP heat shrink tubing (Zeus, 0.125 inch OD) and a hot air gun to shrink around the porous cylinder on one end and a custom prepared septum on the other end (Nusil MED1 4013 silicone molded to 0.113 inch diameter). The reservoir volume (17+/−1 uL) was determined from the difference in weight between empty systems and systems filled with PBS. The PBS was loaded by submerging the systems in PBS and drawing a vacuum. Dry devices were submerged in PBS in microcentrifuge tubes and sterilized by heating to 250° F., 15 psi for 15 minutes in a pressure cooker (Deni, 9760). Two 30G needles were inserted into the septum to fill the devices with PBS. One was used to inject the PBS and the other was bent and used as a vent. After weighing the PBS filled devices, two new needles were inserted through the septum and sufficient BSA solution was injected to fill the needle hub of the vent to approximately ¾ full. The remaining details of the experiment are the same as Example 7.

FIG. 18A displays the measured cumulative release of BSA through the 0.2 media grade sintered porous stainless steel cylinder. A single parameter of Porosity divided by Channel Parameter was determined to be 0.12 by least squares fit of the model to the data. Since the sintered porous structure is cylindrical, the Channel Parameter can be interpreted as effective length of the interconnecting channels that may correspond the Tortuosity, T. Using the Porosity of 0.17 determined by the vendor, the effective length of the channel that may correspond to the Tortuosity was determined to be 1.4. Furthermore, this corresponds to a PA/FL ratio (Release Rate Index) of 0.0475 mm.

FIG. 18B displays the measured cumulative release of BSA through the 0.2 media grade sintered porous stainless steel cylinder for 180 days. A single parameter of Porosity divided by Channel Parameter was determined to be 0.10 by least squares fit of the model to the data. Since the sintered porous structure is cylindrical, the Channel Parameter can be interpreted an effective length of the inter-connecting channels that may correspond to the Tortuosity, T. Using the Porosity of 0.17 determined by the vendor, the effective channel length of the inter-connecting channels that may correspond to the Tortuosity was determined to be 1.7. Furthermore, this corresponds to a PA/FL ratio (Release Rate Index) of 0.038 mm.

Example 9 Calculations of Lucentis™ Concentrations in the Vitreous

The vitreous concentrations of a therapeutic agent can be predicted based on the equations described herein. Table 4 shows the values of the parameters applied for each of Simulation 1, Simulation 2, Simulation 3, Simulation 4, and Simulation 5. The half-life and vitreous volume correspond to a monkey model (J. Gaudreault et al., Preclinical Pharmacokinetics of Ranibizumab (rhuFabV2) after a Single Intravitreal Administration, Invest Ophthalmol V is Sci 2005; 46: 726-733) (Z. Yao et al., Prevention of Laser Photocoagulation Induced Choroidal Neovascularization Lesions by Intravitreal Doses of Ranibizumab in Cynomolgus Monkeys, ARVO 2009 abstract D906). The parameter PA/FL can be varied to determine the release rate profile. For example, the value of A can be about 1 mm², the porosity can be about 0.1 (PA=0.1 mm²) and the length about 1 mm and the channel fit parameter that may correspond to tortuousity can be about 2 (FL=2 mm), such that PA/TL is about 0.05 mm. A person of ordinary skill in the art can determine empirically the area, porosity, length and channel fit parameter for extended release of the therapeutic agent for the extended period based on the teachings described herein.

TABLE 4A Values Values Values Values Values Parameter Simulation 1 Simulation 2 Simulation 3 Simulation 4 Simulation 5 Diffusion coeff (cm2/s) 1.0E−06 1.0E−06 1.0E−06 1.0E−06 1.0E−06 Initial Loading (ug/mL) 10000 10000 10000 10000 10000 Reservoir Vol (ml) 0.05 0.01 0.05 0.01 0.017 PA/FL (mm) 0.0225 0.0225 0.045 0.045 0.047 Half-life (days) 2.63 2.63 2.63 2.63 2.63 Rate constant, k (1/day) 0.264 0.264 0.264 0.264 0.264 Vitreous vol (ml) 1.5 1.5 1.5 1.5 1.5

Table 4B shows the vitreous concentrations calculated for a 0.5 mg bolus injection of Lucentis™ injected into the eye of a monkey using equations described herein and the half-life measured for the monkey listed in Table 4A. The first column used the measured Cmax (Gaudreault et al.) while the second used a calculated Cmax based on the dose and volume of the vitreous. The average concentration of Lucentis™ is about 46 ug/ml. The minimum therapeutic concentration of Lucentis™ is about 0.1 ug/mL, which may correspond to about 100% VGEF inhibition (Gaudreault et al.). Table 4B indicates that a bolus injection of 0.5 mg Lucentis™ maintains a vitreous concentration above 0.1 ug/mL for about a month whether using the measured or calculated Cmax. This is consistent with monthly dosing that has been shown to be therapeutic in clinical studies.

TABLE 4B Predicted Vitreous Predicted Vitreous Time Conc using Meas Cmax Conc using Calc (days) (ug/mL) Cmax (ug/mL) 0 169.00 333.33 1 129.85 256.11 2 99.76 196.77 3 76.65 151.18 4 58.89 116.16 5 45.25 89.24 6 34.76 68.57 7 26.71 52.68 8 20.52 40.48 9 15.77 31.10 10 12.11 23.89 11 9.31 18.36 12 7.15 14.10 13 5.49 10.84 14 4.22 8.33 15 3.24 6.40 16 2.49 4.91 17 1.91 3.78 18 1.47 2.90 19 1.13 2.23 20 0.87 1.71 21 0.67 1.32 22 0.51 1.01 23 0.39 0.78 24 0.30 0.60 25 0.23 0.46 26 0.18 0.35 27 0.14 0.27 28 0.11 0.21 29 0.08 0.16 30 0.06 0.12 31 0.05 0.09 32 0.04 0.07

Tables 4C1, 4C2, 4C3 4C4, and 4C5 show the calculated concentration of Lucentis™ in the vitreous humor for Simulation 1, Simulation 2, Simulation 3, Simulation 4, and Simulation 5 respectively. These results indicate Lucentis™ vitreous concentrations may be maintained above the minimum therapeutic level for about a year or more when released from a device with porous structure characterized by PA/FL≦0.0225 mm and a reservoir volume ≧10 uL.

Simulation 5 corresponds to the devices used in the experiment described in Example 8. This device had a reservoir volume of 17 uL and porous structure characterized by PA/FL=0.047 mm. When this device is loaded with Lucentis™, the loading dose corresponds to ⅓ of the 50 uL currently injected monthly. Calculations that predict vitreous concentrations indicate that this device with one-third of the monthly dose may maintain Lucentis™ therapeutic concentrations for about 6 months. While half of the dose is delivered in the first month and more than 98% delivered at 6 months, therapeutic levels may still be maintained for 6 months.

The ability of the device to release therapeutic agent for an extended time can be described by an effective device half-life. For the device in Example 8, the effective device half-life is 29 days for delivery of Lucentis™. The device can be configured by selection of the reservoir volume and a porous structure with an appropriate PA/FL to achieve the desired effective half-life.

TABLE 4C1 Simulation 1 Predicted Predicted Vitreous Time Rate Predicted Conc (days) (ug/day) % CR (ug/mL) 0 1.9 0.0% 4.9 10 1.9 3.8% 4.7 20 1.8 7.5% 4.5 30 1.7 11.0% 4.4 40 1.7 14.4% 4.2 50 1.6 17.7% 4.0 60 1.5 20.8% 3.9 70 1.5 23.8% 3.7 80 1.4 26.7% 3.6 90 1.4 29.5% 3.5 100 1.3 32.2% 3.3 110 1.3 34.8% 3.2 120 1.2 37.3% 3.1 130 1.2 39.7% 3.0 140 1.1 42.0% 2.9 150 1.1 44.2% 2.7 160 1.0 46.3% 2.6 170 1.0 48.4% 2.5 180 1.0 50.3% 2.4 190 0.9 52.2% 2.3 200 0.9 54.0% 2.3 210 0.9 55.8% 2.2 220 0.8 57.5% 2.1 230 0.8 59.1% 2.0 240 0.8 60.7% 1.9 250 0.7 62.2% 1.9 260 0.7 63.6% 1.8 270 0.7 65.0% 1.7 280 0.7 66.3% 1.7 290 0.6 67.6% 1.6 300 0.6 68.9% 1.5 310 0.6 70.0% 1.5 320 0.6 71.2% 1.4 330 0.5 72.3% 1.4 340 0.5 73.3% 1.3 350 0.5 74.4% 1.3 360 0.5 75.3% 1.2

TABLE 4C2 Simulation 2 Predicted Predicted Vitreous Time Rate Predicted Conc (days) (ug/day) % CR (ug/mL) 0 1.9 0.0% 4.92 10 1.6 17.7% 4.05 20 1.3 32.2% 3.33 30 1.1 44.2% 2.74 40 0.9 54.0% 2.26 50 0.7 62.2% 1.86 60 0.6 68.9% 1.53 70 0.5 74.4% 1.26 80 0.4 78.9% 1.04 90 0.3 82.6% 0.85 100 0.3 85.7% 0.70 110 0.2 88.2% 0.58 120 0.2 90.3% 0.48 130 0.2 92.0% 0.39 140 0.1 93.4% 0.32 150 0.1 94.6% 0.27 160 0.1 95.5% 0.22 170 0.1 96.3% 0.18 180 0.1 97.0% 0.15 190 0.0 97.5% 0.12 200 0.0 98.0% 0.10 210 0.0 98.3% 0.08 220 0.0 98.6% 0.07 230 0.0 98.9% 0.06 240 0.0 99.1% 0.05 250 0.0 99.2% 0.04 260 0.0 99.4% 0.03 270 0.0 99.5% 0.03 280 0.0 99.6% 0.02 290 0.0 99.6% 0.02 300 0.0 99.7% 0.01 310 0.0 99.8% 0.01 320 0.0 99.8% 0.01 330 0.0 99.8% 0.01 340 0.0 99.9% 0.01 350 0.0 99.9% 0.01 360 0.0 99.9% 0.00

TABLE 4C3 Simulation 3 Predicted Predicted Vitreous Time Rate Predicted Conc (days) (ug/day) % CR (ug/mL) 0 3.9 0.0% 9.8 10 3.6 7.5% 9.1 20 3.3 14.4% 8.4 30 3.1 20.8% 7.8 40 2.8 26.7% 7.2 50 2.6 32.2% 6.7 60 2.4 37.3% 6.2 70 2.3 42.0% 5.7 80 2.1 46.3% 5.3 90 1.9 50.3% 4.9 100 1.8 54.0% 4.5 110 1.7 57.5% 4.2 120 1.5 60.7% 3.9 130 1.4 63.6% 3.6 140 1.3 66.3% 3.3 150 1.2 68.9% 3.1 160 1.1 71.2% 2.8 170 1.0 73.3% 2.6 180 1.0 75.3% 2.4 190 0.9 77.2% 2.2 200 0.8 78.9% 2.1 210 0.8 80.5% 1.9 220 0.7 81.9% 1.8 230 0.7 83.3% 1.6 240 0.6 84.5% 1.5 250 0.6 85.7% 1.4 260 0.5 86.8% 1.3 270 0.5 87.7% 1.2 280 0.4 88.7% 1.1 290 0.4 89.5% 1.0 300 0.4 90.3% 1.0 310 0.3 91.0% 0.9 320 0.3 91.7% 0.8 330 0.3 92.3% 0.8 340 0.3 92.9% 0.7 350 0.3 93.4% 0.6 360 0.2 93.9% 0.6

TABLE 4C4 Simulation 4 Predicted Predicted Vitreous Time Rate Predicted Conc (days) (ug/day) % CR (ug/mL) 0 3.89 0.0% 9.83 10 2.64 32.2% 6.67 20 1.79 54.0% 4.52 30 1.21 68.9% 3.06 40 0.82 78.9% 2.08 50 0.56 85.7% 1.41 60 0.38 90.3% 0.95 70 0.26 93.4% 0.65 80 0.17 95.5% 0.44 90 0.12 97.0% 0.30 100 0.08 98.0% 0.20 110 0.05 98.6% 0.14 120 0.04 99.1% 0.09 130 0.02 99.4% 0.06 140 0.02 99.6% 0.04 150 0.01 99.7% 0.03 160 0.01 99.8% 0.02 170 0.01 99.9% 0.01 180 0.00 99.9% 0.01 190 0.00 99.9% 0.01 200 0.00 100.0% 0.00 210 0.00 100.0% 0.00 220 0.00 100.0% 0.00 230 0.00 100.0% 0.00 240 0.00 100.0% 0.00 250 0.00 100.0% 0.00 260 0.00 100.0% 0.00 270 0.00 100.0% 0.00 280 0.00 100.0% 0.00 290 0.00 100.0% 0.00 300 0.00 100.0% 0.00 310 0.00 100.0% 0.00 320 0.00 100.0% 0.00 330 0.00 100.0% 0.00 340 0.00 100.0% 0.00 350 0.00 100.0% 0.00 360 0.00 100.0% 0.00

TABLE 4C5 Simulation 5 Predicted Predicted Vitreous Time Rate Predicted Conc (days) (ug/day) % CR (ug/mL) 0 4.1 0.0% 10.27 10 3.2 21.2% 8.09 20 2.5 38.0% 6.37 30 2.0 51.2% 5.02 40 1.6 61.5% 3.95 50 1.2 69.7% 3.11 60 1.0 76.1% 2.45 70 0.8 81.2% 1.93 80 0.6 85.2% 1.52 90 0.5 88.3% 1.20 100 0.4 90.8% 0.94 110 0.3 92.8% 0.74 120 0.2 94.3% 0.58 130 0.2 95.5% 0.46 140 0.1 96.5% 0.36 150 0.1 97.2% 0.29 160 0.1 97.8% 0.22 170 0.1 98.3% 0.18 180 0.1 98.6% 0.14 190 0.0 98.9% 0.11 200 0.0 99.2% 0.09 210 0.0 99.3% 0.07 220 0.0 99.5% 0.05 230 0.0 99.6% 0.04 240 0.0 99.7% 0.03 250 0.0 99.7% 0.03 260 0.0 99.8% 0.02 270 0.0 99.8% 0.02 280 0.0 99.9% 0.01 290 0.0 99.9% 0.01 300 0.0 99.9% 0.01 310 0.0 99.9% 0.01 320 0.0 100.0% 0.00 330 0.0 100.0% 0.00 340 0.0 100.0% 0.00 350 0.0 100.0% 0.00 360 0.0 100.0% 0.00

Z. Yao et al. (Prevention of Laser Photocoagulation Induced Choroidal Neovascularization Lesions by Intravitreal Doses of Ranibizumab in Cynomolgus Monkeys, ARVO 2009 abstract D906) have performed a preclinical study to determine the lowest efficacious Lucentis™ dose in cynomolgus monkeys that leads to 100% prevention of laser photocoagulation treatment-induced Grade IV choroidal neovascularization (CNV) Lesions.™ This model has been shown to be relevant to AMD. Intravitreal injection of Lucentis™ at all doses tested completely inhibited the development of Grade IV CNV lesions. Table 4D shows predictions of Lucentis™ vitreous concentrations for the lowest total amount of Lucentis™ investigated (intravitreal injection of 5 ug on days 1, 6, 11, 16, 21 and 26), using the equations described herein and pharmacokinetic parameters listed in Table 4A. This data indicates that it is not necessary to achieve the high Cmax of a 0.5 mg single bolus injection in order to be therapeutic.

FIG. 19A compares this predicted profile with that predicted for the device in Example 8. This data further supports that the release profile from a device in accordance with embodiments of the present invention may be therapeutic for at least about 6 months. The single injection of 500 ug corresponds to a 50 uL bolus injection of Lucentis™ that can given at monthly intervals, and the range of therapeutic concentrations of Lucentis™ (ranibizumab) in the vitreous extends from about 100 ug/mL to the minimum inhibitory (therapeutic) concentration of about 0.1 ug/mL at about 1 month, for example. The minimum inhibitory concentration corresponding to the lower end of the range of therapeutic concentrations in the vitreous humor can be determined empirically by one of ordinary skill in the art in accordance with the examples described herein. For example, a lose does study of a series of six Lucentis™ injections, 5 ug each, can be administered so as to provide a concentration in the vitreous of at least about 1 ug/mL, and the therapeutic benefit of the injections assessed as described herein.

TABLE 4D Predicted Lucentis Time Vitreous Conc (days) (ug/mL) 0 0.00 1 3.33 2 2.56 3 1.97 4 1.51 5 1.16 6 4.23 7 3.25 8 2.49 9 1.92 10 1.47 11 4.46 12 3.43 13 2.64 14 2.02 15 1.56 16 4.53 17 3.48 18 2.67 19 2.05 20 1.58 21 4.55 22 3.49 23 2.68 24 2.06 25 1.58 26 4.55 27 3.50 28 2.69 29 2.06 30 1.59 35 0.42 40 0.11 45 0.03 50 0.01 60 0.00 70 0.00 80 0.00 90 0.00

The concentration profiles of a therapeutic agent comprising Lucentis™ were determined as shown below based on the teachings described herein and with drug half-life of nine days for Lucentis™ in the human eye. The examples shown below for injections of the commercially available formulation Lucentis™ and the nine day half life show unexpected results, and that a volume of formulation corresponding to a monthly bolus injection into the device as described herein can provide therapeutic benefit for at least about two months. The device volume and the porous structure can be tuned to receive the predetermined volume of formulation and provide sustained release for an extended time. Additional tuning of the device can include the half-life of the therapeutic agent in the eye, for example nine days for Lucentis™, and the minimum inhibitory concentration of the therapeutic agent as determined based on the teachings as described herein.

FIG. 19B shows determined concentrations of Lucentis™ in the vitreous humor for a first 50 uL injection into a 25 uL device and a second 50 uL injection at 90 days. The calculations show that the 50 uL dosage of the monthly FDA approved bolus injection can be used to treat the eye for about 90 days, and that the injections can be repeated to treat the eye, for example at approximately 90 day intervals. The Lucentis™ may comprise a predetermined amount of the commercially available formulation injected into the device. The commercially available formulation of Lucentis™ has a concentration of ranibizumab of 10 mg/mL, although other concentrations can be used for example as described herein below with reference to a 40 mg/mL solution of injected ranibizumab. The predetermine amount corresponds to the amount of the monthly bolus injection, for example 50 uL. The therapeutic device may comprise a substantially fixed volume container reservoir having a volume of 25 uL, such that a first 25 uL portion of the 50 uL injection is contained in the reservoir for sustained and/or controlled release and a second 25 uL portion of the 50 uL injection is passed through the porous structure and released into the vitreous with a 25 uL bolus. The filling efficiency of the injection into the device may comprise less than 100%, and the reservoir volume and injection volume can be adjusted based on the filling efficiency in accordance with the teachings described herein. For example, the filling efficiency may comprise approximately 90%, such that the first portion comprises approximately 22.5 uL contained in the chamber of the container reservoir and the second portion comprises approximately 27.5 uL passed through the device for the 50 uL injected into the therapeutic device. The initial concentration of Lucentis™ in the vitreous humor corresponds to about 60 ug/mL immediately following injection into the reservoir device. The concentration of Lucentis™ in the vitreous humor decreases to about 3.2 ug/mL at 90 days. A second 50 uL injection of Lucentis™ approximately 90 days after the first injection increases the concentration to about 63 ug/mL. The concentration of Lucentis™ in the vitreous humor decreases to about 3.2 ug/mL at 180 days after the first injection and 90 days after the second injection. These calculations show that the concentration of Lucentis™ can be continuously maintained above a minimum inhibitory concentration of about 3 ug per ml with the 50 uL injection into the device. Additional injections can be made, for example every 90 days for several years to deliver the therapeutic agent to treat the patient.

FIG. 19C shows determined concentrations of Lucentis™ in the vitreous humor for a first 50 uL injection into a 32 uL device and a second 50 uL injection at a time greater than 90 days. The calculations show that the 50 uL dosage of the monthly FDA approved bolus injection can be used to treat the eye for about 90 days, and that the injections can be repeated to treat the eye, for example at approximately 90 day intervals. The Lucentis™ may comprise a predetermined amount of the commercially available formulation injected into the device. The predetermine amount corresponds to the amount of the monthly bolus injection, for example 50 uL. The therapeutic device may comprise a substantially fixed volume container reservoir having a volume of 32 uL, such that a first 32 uL portion of the 50 uL injection is contained in the reservoir for sustained and/or controlled release and a second 18 uL portion of the 50 uL injection is passed through the porous structure and released into the vitreous with an 18 uL bolus. The filling efficiency of the injection into the device may comprise less than 100%, and the reservoir volume and injection volume can be adjusted based on the filling efficiency in accordance with the teachings described herein. For example, the filling efficiency may comprise approximately 90%, such that the first portion comprises approximately 29 uL contained in the chamber of the reservoir container and the second portion comprises approximately 21 uL passed through the device for the 50 uL of Lucentis™ injected into the therapeutic device. The initial concentration of Lucentis™ in the vitreous humor corresponds to about 45 ug/mL immediately following injection into the reservoir device. The concentration of Lucentis™ in the vitreous humor decreases to about 4 ug/mL at 90 days. A second 50 uL injection of Lucentis™ approximately 90 days after the first injection increases the concentration to about 50 ug/mL. The concentration of Lucentis™ in the vitreous humor decreases to about 4 ug/mL at 180 days after the first injection and 90 days after the second injection. These calculations show that the concentration of Lucentis™ can be continuously maintained above a minimum inhibitory concentration of about 4 ug per ml with the 50 uL injection into the device. Additional injections can be made every 120 days for several years to deliver the therapeutic agent to treat the patient. The injections can be made more frequently or less frequently, depending upon the minimum inhibitory concentration, the release rate profile, and the discretion of the treating physician.

FIG. 19D shows determined concentrations of Lucentis™ in the vitreous humor for a first 50 uL injection into a 50 uL device and a second 50 uL injection at 90 days. The calculations show that the 50 uL dosage of the monthly FDA approved bolus injection can be used to treat the eye for about 90 days, and that the injections can be repeated to treat the eye, for example at approximately 90 day intervals. The Lucentis™ may comprise a predetermined amount of the commercially available formulation injected into the device. The filling efficiency of the injection into the device may comprise less than 100%, and the reservoir volume and injection volume can be adjusted based on the filling efficiency in accordance with the teachings described herein. For example, the filling efficiency may comprise approximately 90%, such that the first portion comprises approximately 45 uL contained in the chamber of the reservoir container and the second portion comprises approximately 5 uL passed through the device for the 50 uL of Lucentis™ injected into the therapeutic device. The initial concentration of Lucentis™ in the vitreous humor corresponds to about 11 ug/mL immediately following injection into the reservoir device. The concentration of Lucentis™ in the vitreous humor decreases to about 5.8 ug/mL at 90 days. A second 50 uL injection of Lucentis™ approximately 90 days after the first injection increases the concentration to about 17 ug/mL. The concentration of Lucentis™ in the vitreous humor decreases to about 5.8 ug/mL at 180 days after the first injection and 90 days after the second injection. These calculations show that the concentration of Lucentis™ can be continuously maintained above a minimum inhibitory concentration of about 5 ug per ml with the 50 uL injection into the device. Additional injections can be made, for example every 90 days for several years to deliver the therapeutic agent to treat the patient.

FIG. 19E shows determined concentrations of Lucentis™ in the vitreous humor for a first 50 uL injection into a 50 uL device and a second 50 uL injection at 90 days. The calculations show that the 50 uL dosage of the monthly FDA approved bolus injection can be used to treat the eye for about 130 days, and that the injections can be repeated to treat the eye, for example at approximately 120 day intervals. The Lucentis™ may comprise a predetermined amount of the commercially available formulation injected into the device. The filling efficiency of the injection into the device may comprise less than 100%, and the reservoir volume and injection volume can be adjusted based on the filling efficiency in accordance with the teachings described herein. For example, the filling efficiency may comprise approximately 90%, such that the first portion comprises approximately 45 uL contained in the chamber of the reservoir container and the second portion comprises approximately 5 uL passed through the device for the 50 uL of Lucentis™ injected into the therapeutic device. The initial concentration of Lucentis™ in the vitreous humor corresponds to about 11 ug/mL immediately following injection into the reservoir device. The concentration of Lucentis™ in the vitreous humor decreases to about 4 ug/mL at 133 days. A second 50 uL injection of Lucentis™ approximately 130 days after the first injection increases the concentration to about 15 ug/mL. Based on these calculations, the concentration of Lucentis™ in the vitreous humor decreases to about 4 ug/mL at 266 days after the first injection and 90 days after the second injection. These calculations show that the concentration of Lucentis™ can be continuously maintained above a minimum inhibitory concentration of about 4 ug per ml with the 50 uL injection into the device. Additional injections can be made, for example every 90 days for several years to deliver the therapeutic agent to treat the patient.

Although FIGS. 19B to 19P make reference to injections of commercially available off the shelf formulations of Lucentis™, therapeutic device 100 can be similarly configured to release many formulations of the therapeutic agents as described herein, for example with reference to Table 1A and the Orange Book of FDA approved formulations and similar books of approved drugs in many countries, unions and jurisdictions such as the European Union. For example, based on the teachings described herein, one can determine empirically the parameters of therapeutic device 100 so as to tune the device to receive a injection of a commercially available formulation corresponding to a monthly bolus injections and release the injected therapeutic agent with amounts above the minimum inhibitory concentration for an extended time of at least about two months, for example, at least about three months, for example, or about four months, for example.

FIG. 19F shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 50 uL device having a release rate index of 0.05. The concentration of ranibizumab in the vitreous humor peaks at around 9 ug/mL and is at or above 4 ug/mL for about 145 days. The concentration remains above about 1 ug/mL for about 300 days. The concentration is about 0.6 ug/mL at 360 days, and can be suitable for treatment with a single injection up to one year, based on a minimum inhibitory concentration of about 0.5. The minimum inhibitory concentration can be determined empirically by a person of ordinary skill in the art based on the teachings described herein.

FIG. 19G shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 75 uL device having a release rate index of 0.05. The concentration of ranibizumab in the vitreous humor peaks at around 6.5 ug/mL and is at or above 4 ug/mL for about 140 days. The concentration remains above about 1 ug/mL for about 360 days.

FIG. 19H shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 100 uL device having a release rate index of 0.05. The concentration of ranibizumab in the vitreous humor peaks at around 5 ug/mL and is at or above 4 ug/mL for about 116 days. The concentration remains above about 1 ug/mL for more than 360 days and is about 1.5 ug/mL at 360 days.

FIG. 19I shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL device having a release rate index of 0.05. The concentration of ranibizumab in the vitreous humor peaks at around 4.3 ug/mL and does not equal or exceed 4 ug/mL. The concentration remains above about 1 ug/mL for more than 360 days and is about 1.5 ug/mL at 360 days.

FIG. 19J shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 150 uL device having a release rate index of 0.05. The concentration of ranibizumab in the vitreous humor peaks at around 3.5 ug/mL and does not equal or exceed 4 ug/mL. The concentration remains above about 1 ug/mL for more than 360 days and is about 1.5 ug/mL at 360 days.

FIG. 19K shows determined concentrations of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 100 uL device having a release rate index of 0.1. These determined concentrations are similar to the determined concentrations of FIG. 19F, and show that the release rate index of the porous structure can be tuned with the device volume to provide therapeutic concentration profile for an extended time. For example, by doubling the volume of the reservoir so as to half the concentration of therapeutic agent in the vitreous, the release rate index can be doubled so as to provide a similar therapeutic concentration profile. The concentration of ranibizumab in the vitreous humor peaks at around 9 ug/mL and is at or above 4 ug/mL for about 145 days. The concentration remains above about 1 ug/mL for about 300 days. The concentration is about 0.6 ug/mL at 360 days.

FIGS. 19L to 19P show examples of release rate profiles with 125 uL reservoir devices having the RRI vary from about 0.065 to about 0.105, such that these devices are tuned to receive the 50 uL injection of Lucentis™ and provide sustained release above a minimum inhibitory concentration for at least about 180 days. These calculations used a drug half life in the vitreous of 9 days to determine the profiles and 100% efficiency of the injection.

FIG. 19L shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.105. The concentration of ranibizumab in the vitreous at 180 days is about 3.128 ug/mL.

FIG. 19M shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.095. The concentration of ranibizumab in the vitreous at 180 days is about 3.174 ug/mL.

FIG. 19N shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.085. The concentration of ranibizumab in the vitreous at 180 days is about 3.185 ug/mL.

FIG. 19O shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.075. The concentration of ranibizumab in the vitreous at 180 days is about 3.152 ug/mL.

FIG. 19P shows determined concentration profiles of ranibizumab in the vitreous humor for a 50 uL Lucentis™ injection into a 125 uL reservoir device having a release rate index of 0.065. The concentration of ranibizumab in the vitreous at 180 days is about 3.065 ug/mL.

The optimal RRI for the concentration of ranibizumab at 180 days for a reservoir volume of 125 uL and a 50 uL injection of Lucentis™ can be calculated based on the equations as described herein, and is about 0.085. Although the optimal value is 0.085, the above graphs show that the reservoir and release rate index can be tuned to provide therapeutic amounts of ranibizumab above a minimum inhibitory concentration of 3 ug/mL with many values of the RRI and reservoir volume, for example values within about +/−30% to +/−50% of the optimal values for the predetermined quantity of Lucentis™ formulation.

Table 4E shows values of parameters used to determine the ranibizumab concentration profiles as in FIGS. 19K to 19P.

TABLE 4E Diffusion coeff (cm2/s) 1.0E−06 Initial Loading (ug/mL) 10000 Reservoir Vol (ml) 0.125 PA/TL (mm) varied Half-life (days) 9 Rate constant, k (1/day) 0.077 Vitreous vol (ml) 4.5 Volume injected (mL) 0.05 Time step (days) 0.1 Time between refills (days) 180 Refill Efficiency 100%

The therapeutic concentration profiles of examples of FIGS. 19B to 19P were determined with a nine day half-life of the drug in the vitreous humor of the human eye. The therapeutic concentration profiles can be scaled in accordance with the half life of the therapeutic agent in the eye. For example, with an eighteen day half life, the concentration in these examples will be approximately twice the values shown in the graph at the extended times, and with a 4.5 day half-life, the concentrations will be approximately half the values shown with the extended times. As an example, a drug half life of eighteen days instead of nine days will correspond to a concentration of about 1.4 ug/mL at 360 days instead of about 0.6 ug/mL as shown in FIGS. 19F and 19K. This scaling of the concentration profile based on drug half life in the vitreous can be used to tune the volume and sustained release structures of the therapeutic device, for example in combination with the minimum inhibitory concentration. Although the above examples were calculated for Lucentis™, similar calculations can be performed for therapeutic agents and formulations as described herein, for example as described herein with reference to Table 1A.

Based on the teachings described herein, a person of ordinary skill in the art can determine the release rate index and volume of the therapeutic agent based on the volume of formulation injected into the device and minimum inhibitory concentration. This tuning of the device volume and release rate index based on the volume of formulation injected can produce unexpected results. For example, with a clinically beneficial minimum inhibitory concentration of about 4 ug/mL, a single bolus injection corresponding to a one month injection can provide a therapeutic benefit for an unexpected three or more months, such as four months. Also, for a clinically beneficial minimum inhibitory concentration of at least about 1.5 ug/mL, a single bolus injection corresponding to a one month injection can provide a therapeutic benefit for an unexpected twelve or more months. The clinically beneficial minimum inhibitory concentration can be determined empirically based on clinical studies as described herein.

Although the examples of FIGS. 19F to 19K assumed a filling efficiency of one hundred percent, a person of ordinary skill in the art based on the teachings as described herein can determine the release rate profiles for filling efficiencies less than 100%, for example with 90% filling efficiency as shown above. Such filling efficiencies can be achieved with injector apparatus and needles as described herein, for example with reference to FIGS. 7, 7A, 7A1 and 7A2.

FIG. 19Q shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL concentrated Lucentis™ (40 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about nine days. These data show that an injection of 10 uL of concentrated (40 mg/mL) Lucentis™ into a 10 uL reservoir device can maintain the concentration of Lucentis™ above at least about 2 ug/mL for at least about 180 days when the half life of Lucentis™ in the vitreous is at least about nine days, and that the device can provide therapeutic concentrations for an extended time of at least about 180 days when the minimum inhibitory concentration comprises no more than about 2 ug/mL.

FIG. 19R shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL concentrated Lucentis™ (40 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about five days. These data show that an injection of 10 uL of concentrated (40 mg/mL) Lucentis™ into a 10 uL reservoir device can maintain the concentration of Lucentis™ above at least about 1 ug/mL for at least about 180 days when the half life of Lucentis™ in the vitreous is at least about five days, and that the device can provide therapeutic concentrations for an extended time of at least about 180 days when the minimum inhibitory concentration comprises no more than about 1 ug/mL.

FIG. 19S shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL standard Lucentis™ (10 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about nine days. These data show that an injection of 10 uL of standard commercially available (10 mg/mL) Lucentis™ into a 10 uL reservoir device can maintain the concentration of Lucentis™ above at least about 0.5 ug/mL for at least about 180 days when the half life of Lucentis™ in the vitreous is at least about nine days, and that the device can provide therapeutic concentrations for an extended time of at least about 180 days when the minimum inhibitory concentration comprises no more than about 0.5 ug/mL.

FIG. 19T shows determined concentrations of ranibizumab in the vitreous humor for a 10 uL standard Lucentis™ (10 mg/mL) injection into a 10 uL device having a release rate index of 0.01 and in which the ranibizumab has a half life in the vitreous humor of about five days. These data show that an injection of 10 uL of standard commercially available (10 mg/mL) Lucentis™ into a 10 uL reservoir device can maintain the concentration of Lucentis™ above at least about 0.25 ug/mL for at least about 180 days when the half life of Lucentis™ in the vitreous is at least about five days, and that the device can provide therapeutic concentrations for an extended time of at least about 180 days when the minimum inhibitory concentration comprises no more than about 0.25 ug/mL.

Example 10 Calculations of Target Device Characteristics for a Device Releasing Drug from a Suspension

Triamcinolone acetonide is a corticosteroid used to treat uveitis and other diseases involving ocular inflammation. A 4 mg intravitreal injection of a suspension of triamcinolone acetonide may be administered to patients unresponsive to topical corticosteroids. Calculations as described herein were performed to determine the characteristics of a device that would release therapeutic amounts for an extended period of time.

Consider a device with 10 uL reservoir volume loaded with 0.4 mg using a commercial drug product (40 mg/mL triamcinolone acetonide). Calculations were performed using a value of 19 ug/mL for the solubility of triamcinolone acetonide measured at 37° C. in 0.2. M potassium chloride and a diffusion coefficient of 5 e-6 cm²/s representative of a small molecule. The target release rate is 1 ug/day based upon published clinical data. As an example, consider the 0.2 media grade stainless steel characterized in Example 8 with P/F=0.12 and a thickness of 0.5 mm. Using these values, the calculations suggest that therapeutic release rates could be achieved with a device containing a porous cylinder with an area of 5 mm². This could be achieved with a cylindrical device having an inner diameter of 2 mm and a length of porous tubing of 1 mm. Alternatively, the end of the device could be a porous cup with height of 0.8 mm (0.5 mm thick porous face plus 0.3 mm length) of porous tubing.

Assuming a typical value of 3 hours for the half-life of a small molecule in the vitreous, these calculations suggest the device will achieve a steady state triamcinolone acetonide vitreous concentration of 0.12 ug/mL.

Example 11 Calculation of Release Rate Profile for a Therapeutic Agent Suspension Disposed in the Reservoir and Released Through the Porous Frit Structure

FIG. 20 shows a calculated time release profile of a therapeutic agent suspension in a reservoir as in Example 10. Triamcinolone Acetonide concentrations in human vitreous were determined for a 10 uL device with RRI of 1.2 mm and shown. The calculations were based on the equations shown above for the suspension. The profile was generated with numerical simulation. Assuming a constant delivery rate of 1 ug/day starting instantaneously at T=0, the concentration in the vitreous of a human eye can reach within 99% of the steady state value in 1 day. At the other end of the drug release profile, the simulation shows the vitreous concentration when substantially all of the solid drug is gone; more than 99% of the dissolved drug is delivered within a day.

Assuming a typical value of 3 hours for the half-life of a small molecule in the vitreous, these calculations indicate that the device will achieve a substantially steady state triamcinolone acetonide vitreous concentration of 0.12 ug/mL in the rabbit or monkey (vitreous volume of 1.5 mL) or 0.04 ug/mL in the human eye (vitreous volume of 4.5 mL). The steady state vitreous concentration are maintained until there is no longer solid triamcinolone acetonide of the suspension in the reservoir. As shown in FIG. 20, a device with a 10 uL reservoir volume and Release Rate Index of 1.2 mm can produce substantially constant drug concentration amounts in the human vitreous for approx. 400 days. Additional experimental and clinical studies based on the teachings described herein can be conducted to determine the release rate profile in situ in human patients, and the drug reservoir volume and release rate index configured appropriately for therapeutic benefit for a target time of drug release. The substantially constant drug concentration amounts can provide substantial therapy and decrease side effects. Similar studies can be conducted with many suspensions of many therapeutic agents as described herein, for example suspensions of corticosteroids and analogues thereof as described herein.

Example 12 Measured of Release Rate Profiles for Avastin™ Through the Porous Frit Structures Coupled to Reservoirs of Different Sizes and Dependence of Release Rate Profile on Reservoir Size

FIG. 21 shows a release rate profiles of therapeutic devices comprising substantially similar porous frit structures and a 16 uL reservoir and a 33 uL reservoir. The release rate index of each frit was approximately 0.02. The release rate for two therapeutic devices each comprising a 16 uL reservoir and two therapeutic devices each comprising a 33 uL reservoir are shown. The device comprising the 33 uL reservoir released the Avastin™ at approximately twice the rate of the device comprising 16 uL reservoir. These measured data show that the release rate index and reservoir size can determine the release rate profile, such that the release rate index and reservoir can be configured to release the therapeutic agent for an extended time.

First Study: The data were measured with a 16 uL volume reservoir as follows: 25 mg/mL Avastin™; Frit #2 (0.031×0.049″, media grade 0.2 um, 316L SS, Mott Corporation); Substantially similar materials as Example 8 above (Teflon heat shrink tubing and silicone septum); 37C; Data is truncated when one of two replicates formed a bubble. See data in Table 5A below.

Second Study: The data were measured with a 33 uL reservoir as follows: 25 mg/mL Avastin™; Frit #2 (0.031×0.049″, media grade 0.2 um, 316L SS, Mott Corporation); Machined from solid beading, closed with a metal rod; 37C; Data is truncated when one of two replicates formed a bubble.

TABLE 5A Measured Release of Avastin ™ and RRI. Volume (uL) Device RRI (mm) SS (ug/day)2 33 1 0.015 0.35 33 2 0.018 0.16 16 1 0.018 0.05 16 2 0.022 0.06 Mean 0.018 % CV 16% SS is the average of the squared difference between predicted and measured rates, and % CV refers to the coefficient of variation, a known statistical parameter.

Example 13 Measured Release Rate Profiles for Avastin™ Through the Porous Frit Structures

FIG. 22A shows cumulative release for Avastin™ with porous fit structures having a thickness of 0.049″. The experiments used: 25 mg/mL Avastin™; Frit #2 (0.031×0.049″, media grade 0.2 um, 316L SS, Mott Corporation); Machined polycarbonate surrogate with screw; Reservoir Volume 37 uL; 37C. The device number and corresponding RRI's for each tested device are listed in Table 5B below. The determined RRI based on measurements is 0.02, consistent with the model for release of the therapeutic agent as described herein. Although some variability is noted with regards to the measured RRI for each test device, the RRI for each device can be used to determine the release of the therapeutic agent, and the porous structure can be further characterized with gas flow as described herein to determine the RRI prior to placement in the patient.

TABLE 5B Device RRI (mm) SS (ug/day)2  1 0.029 26.0  2 0.027 8.5  5 0.018 3.7 30 0.013 0.1 31 0.013 0.1 32 0.015 0.7 33 0.022 30.5 Mean 0.020 % CV 34%

FIG. 22B1 shows cumulative release for Avastin™ with porous fit structures having a thickness of 0.029″. The experiments used: 25 mg/mL Avastin™; Frit #3 (0.038×0.029″, media grade 0.2 um, 316L SS, Mott Corporation); Machined polycarbonate surrogate with screw; Reservoir Volume 37 uL; 37C. The device number and corresponding RRI's for each tested device are listed in Table 5C below. The determined RRI based on measurements is 0.034, consistent with the model for release of the therapeutic agent as described herein. Although some variability is noted with regards to the measured RRI for each test device, the RRI for each device can be used to determine the release of the therapeutic agent, and the porous structure can be further characterized with gas flow as described herein to determine the RRI prior to placement in the patient.

TABLE 5C Device RRI (mm) SS (ug/day)2  9 0.033 0.7 10 0.044 10.8 13 0.030 0.7 27 0.043 15.8 28 0.033 2.6 34 0.030 0.9 35 0.027 0.3 36 0.034 5.5 Mean 0.034 % CV 19%

Table 5D shows an update to Table 5B showing experimental results for up to 130 days. Similarly, Table 5E is an update to Table 5C. In both cases, the RRI was determined by fitting the rate data from each device. For the analysis of data up to 130 days, the first data point is excluded from the fit because the model assumes the maximum delivery rate occurs at time zero while there is some startup time often associated with measured release profiles. The startup time may be related to the time it takes to displace all of the air in the fit. Use of different techniques to displace the air in the frit may reduce the startup time.

This early data has some noise that appears to be related to experimental issues such as contamination from excess protein that is present on the screw from filling the device and was not completely rinsed off at the start of the experiment. The contamination appears to occur randomly as receiver liquid may rinse off the protein while transferring the device from vial to vial at some timepoints but not others. A more accurate assessment of RRI can be obtained by using devices that had fewer or no outliers, as indicated by low values of SS. When this is done, the RRIs from Table 5D and 5E are 0.014 and 0.030 mm, respectively. Similar values for RRI are obtained from data up to 45 days and data up to 130 days, supporting the validity of the model.

TABLE 5D Up to 45 Days Up to 130 Days SS SS Device RRI (mm) (ug/day){circumflex over ( )}2 RRI (mm) (ug/day){circumflex over ( )}2  1 0.029 26.0 0.032 13.7  2 0.027 8.5 0.028 5.5  5 0.018 3.7 0.014 1.7 30 0.013 0.1 0.021 4.8 31 0.013 0.1 0.022 9.3 32 0.015 0.7 0.023 3.4 33 0.022 30.5 0.028 16.4 Mean 0.020 0.024 % CV 34% 24% Mean for 0.014 0.014 SS < 2

TABLE 5E Up to 45 Days Up to 130 Days SS SS Device RRI (mm) (ug/day){circumflex over ( )}2 RRI (mm) (ug/day){circumflex over ( )}2  9 0.033 0.7 0.034 4.4 10 0.044 10.8 0.034 2.0 13 0.030 0.7 0.044 11.6 27 0.043 15.8 0.045 6.8 28 0.033 2.6 0.031 0.5 34 0.030 0.9 0.030 0.7 35 0.027 0.3 0.029 1.3 36 0.034 5.5 0.034 5.9 Mean 0.034 0.035 % CV 19% 17% Mean for 0.030 0.030 SS < 2

FIG. 22B2 shows rate of release for Avastin™ with porous fit structures having a thickness of 0.029″ as in FIG. 22B1. The rate of release can be determined from the measurements and the cumulative release. The outliers in this data can be related to measurement error, such as contamination that provides a signal in the mBCA protein assay.

FIG. 23A shows cumulative release for Avastin™ with a reservoir volume of 20 uL. The experiment used: 25 mg/mL Avastin™; Frit #6 (0.038×0.029″, media grade 0.2 um, 316L SS, Mott Corporation); Machined polycarbonate surrogate with screw; 37C. The determined RRI based on measurements is 0.05 mm, consistent with the model for release of the therapeutic agent as described herein.

FIG. 23A-1 shows cumulative release to about 90 days for Avastin™ with a reservoir volume of 20 uL as in FIG. 23A. The RRI of 0.053 mm corresponds substantially to the RRI of 0.05 of FIG. 23 and demonstrates stability of the release of therapeutic agent through the porous structure.

FIG. 23B shows rate of release as in FIG. 23A. The release rate data show a rate of release from about 5 ug per day to about 8 ug per day. Although the initial release rate at the first day is slightly lower than subsequent rates, the rate of release is sufficiently high to provide therapeutic effect in accordance with the drug release model. Although there can be an initial period of about a few days for the release rate profile to develop, possibly related to wetting of the interconnecting channels of the porous structure, the release rate profile corresponds substantially to the release rate index (RRI) of 0.05. Based on the teachings described herein, a person of ordinary skill in the art could determine the release rate profile with additional data for an extended time of at least about one month, for example at least about three months, six months or more, so as to determine the release rate profile for an extended time.

FIG. 23B-1 shows rate of release as in FIG. 23A-1.

FIG. 24A shows cumulative release for Avastin™ with a 0.1 media grade porous frit structure. This experiment used: 25 mg/mL Avastin™; Frit #5 (0.038×0.029″, media grade 0.1 um, 316L SS, Mott Corporation); Machined polycarbonate surrogate with screw; Reservoir Volume 20 uL; 37C. The determined RRI based on measurements is 0.03, consistent with the model for release of the therapeutic agent as described herein.

FIG. 24A-1 shows cumulative to about 90 days release for Avastin™ with a 0.1 media grade porous frit structure as in FIG. 24A. The release rate of 0.038 mm corresponds substantially to the release rate of 0.03 of FIG. 24A and demonstrates the stability of release of the therapeutic agent through the porous structure.

FIG. 24B shows rate of release as in FIG. 24A. The release rate data show a rate of release from about 2 ug per day to about 6 ug per day. Although the initial release rate at the first day is slightly lower than subsequent rates, the rate of release is sufficiently high to provide therapeutic effect in accordance with the drug release model. Although there can be an initial period of a few days for the release rate profile to develop, possibly related to wetting of the interconnecting channels of the porous structure, the release rate profile corresponds substantially to the release rate index (RRI) of 0.03. Based on the teachings described herein, a person of ordinary skill in the art could determine the release rate profile with additional data for an extended time of at least about one month, for example at least about three months, six months or more, so as to determine the release rate profile for an extended time.

FIG. 24B-1 shows rate of release as in FIG. 24A-1.

Example 14 Determination of Therapeutic Device Size and Lifetime based on Minimum Inhibitory Concentration In Vivo of Therapeutic Agent

Numerical calculations were performed to determine therapeutic device sizes, release rate profiles and expected therapeutic agent concentration in the reservoir. The concentration in the reservoir may correspond to the useful lifetime of the device, or time between injections of therapeutic agent into the reservoir or other replacement of the therapeutic agent.

Table 6A shows the number days of therapeutic agent is released from the device with concentration amounts at or above the MIC. These number of days correspond to an effective lifetime of the device or effective time between injections into the device. The calculations show the number of days of the extended time release based the RRI and MIC for a 20 uL reservoir volume having a drug concentration disposed therein of 10 mg/ml. The RRI ranged from 0.01 to 0.1 and the MIC ranged from 0.1 to 10, and can be determined with experimental and clinical studies as described herein. The half-life of therapeutic agent in the vitreous was modeled as 9 days, based on human data. The Cmax indicates the maximum concentration of therapeutic agent in the vitreous humor, for example within a few days of placement or injection of the therapeutic agent in the device These data indicate that the device can maintain the concentration of therapeutic agent for about 756 days, 385 days, 224 days, and 62 day for MIC's of 0.1, 0.5, 1, 2 and 4 ug/ml, respectively. For example, the therapeutic agent may comprise Lucentis™ having an MIC of about 0.5 and the device may maintain therapeutic concentrations of the agent for one year. These numerical data also show a concentration of therapeutic agent released from the device within a range of the current clinical bolus injections. For example, the Cmax ranges from 2.1 to 11.9 based on the RRI from 0.01 to 0.1 respectively, such that the maximum release of therapeutic agent such as Lucentis™ is within a safe range for the patient.

A person of ordinary skill in the art can conduct experiments to determine the stability of the therapeutic agent such as Lucentis™ in the reservoir, and adjust the size of the reservoir, time between injections or removal. The therapeutic agent can be selected and formulated so as to comprise a stability suitable for use in the therapeutic device.

TABLE 6A Calculations for Time (days) above MIC (20 μL Reservoir Volume, T½ = 9 days, Drug Conc. in Reservoir = 10 mg/ml) Cmax MIC (μg/ml) RRI (μg/ml) 0.1 0.5 1 2 4 7 10 0.01 2.1 756 385 224 62 0 0 0 0.02 3.8 467 280 200 119 0 0 0 0.04 6.5 281 188 148 108 66 0 0 0.06 8.6 209 147 120 93 65 40 0 0.08 10.4 170 124 103 83 61 42 14 0.1 11.9 146 109 92 75 58 42 30

Table 6B. Shows calculations for time (days) above the MIC for a therapeutic device comprising a 20 μL Volume, Vitreous T1/2=9 days, and Drug Conc. in Reservoir=40 mg/ml. The embodiments of Table 6B include similar components to the embodiments of Table 6A and the improved time above MIC achieved with concentration of 40 mg/ml. For example, the time above the MIC can be 1079, 706, 546, 385, 225, 95, for MIC's of 0.1 0.5, 1, 2, 4, and 7 ug/ml, respectively. For example, the therapeutic agent may comprise Lucentis™ having an MIC of about 0.5 and the device may maintain therapeutic concentrations of the therapeutic agent for about 2 years. These numerical data also show a concentration of therapeutic agent released from the device within a range of the current clinical bolus injections. For example, the Cmax ranges from 8.4 to 47.6 based on the RRI from 0.01 to 0.1 respectively, such that the maximum release of therapeutic agent such as Lucentis™ is within a safe range for the patient.

A person of ordinary skill in the art can conduct experiments to determine the stability of the therapeutic agent such as Lucentis™ in the reservoir, and adjust the size of the reservoir, time between injections or removal. The therapeutic agent can be selected and formulated so as to comprise a stability suitable for use in the therapeutic device.

TABLE 6B Calculations for Time (days) above MIC (20 μL Volume, T½ = 9 days, Drug Conc. in Reservoir = 40 mg/ml) Cmax MIC (μg/ml) RRI (μg/ml) 0.1 0.5 1 2 4 7 10 0.01 8.4 1079 706 546 385 225 95 0 0.02 15.1 626 440 360 280 200 135 93 0.04 25.9 361 268 228 188 148 115 94 0.06 34.4 262 200 174 147 120 98 84 0.08 41.5 210 164 144 124 103 87 76 0.1 47.6 179 141 125 109 92 79 70

Table 6C. Shows calculations for time (days) above the MIC for a therapeutic device comprising a 50 μL Volume, Vitreous T1/2=9 days, and Drug Conc. in Reservoir=40 mg/ml. The embodiments of Table 6B include similar components to the embodiments of Table 6A and the improved time above MIC achieved with concentration of 40 mg/ml. For example, the time above the MIC can be 2706, 1737, 1347, 944, 542 and 218, for MIC's of 0.1 0.5, 1, 2, 4, and 7 ug/ml, respectively. For example, the therapeutic agent may comprise Lucentis™ having an MIC of about 0.5 and the device may maintain therapeutic concentrations of the therapeutic agent for more than about 2 years. These numerical data also show a concentration of therapeutic agent released from the device within a range of the current clinical bolus injections. For example, the Cmax ranges from 9.1 to 64.7 ug/ml based on the RRI from 0.01 to 0.1 respectively, such that the maximum release of therapeutic agent such as Lucentis™ is within a safe range for the patient.

A person of ordinary skill in the art can conduct experiments to determine the stability of the therapeutic agent such as Lucentis™ in the reservoir, and adjust the size of the reservoir, time between injections or removal. The therapeutic agent can be selected and formulated so as to comprise a stability suitable for use in the therapeutic device.

TABLE 6C Calculations for Time (days) above MIC (50 μL Volume, T½ = 9 days, Drug Conc. in Reservoir = 40 mg/ml) Cmax MIC (μg/ml) RRI (μg/ml) 0.1 0.5 1 2 4 7 10 0.01 9.1 2706 1737 1347 944 542 218 0 0.02 17.2 1560 1082 880 679 478 316 213 0.04 31.5 887 648 547 446 346 265 213 0.06 43.8 635 476 408 341 274 220 186 0.08 54.8 501 381 331 281 230 190 164 0.1 64.7 417 321 281 240 200 168 147

The examples shown in Tables 6A to 6C can be modified by one of ordinary skill in the art in many ways based on the teachings described herein. For example, the 50 uL reservoir may comprise an expanded configuration of the reservoir after injection of the therapeutic device. The reservoir and/or quantity of therapeutic agent can be adjusted so as to provide release for a desired extended time.

The porous fit structure as described herein can be used with many therapeutic agents, and may limit release of therapeutic agent that has degraded so as to form a particulate, for example. Work in relation to embodiments suggests that at least some therapeutic agents can degrade so as to form a particulate and that the particulate comprising degraded therapeutic agent may have an undesired effect on the patient, and the porous fit structure as described herein may at least partially filter such particulate so as to inhibit potential side effects of degraded therapeutic agent.

Table 6D shows examples of sizes of therapeutic devices that can be constructed in accordance with the teachings described herein, so as to provide a suitable volume of the drug reservoir within the container and such devices may comprise many lengths, widths and structures as described herein. For example the frit outside diameter (hereinafter “OD”) can be configured in many ways and may comprise about 1 mm, for example, or about 0.5 mm. The length of the fit (thickness) may comprise about 1 mm. The volume of the frit can be, for example, about 0.785 uL, or about 0.196 uL, for example. The volume of the reservoir can be from about 0.4 uL to about 160 uL, for example. The volume of the therapeutic device can be from about 0.6 uL to about 157 uL, and can be positioned in many ways, for example with a lumen and may comprise a substantially fixed volume reservoir or an expandable reservoir. The cross sectional width of the device may correspond to many sizes, for example many radii, and the radius can be within a range from about 0.3 mm to about 3.5 mm, for example. The cross-section width and corresponding diameters of the device can be within a range from about 0.6 mm to about 7 mm. The length of the device, including the porous structure, container and retention structure can be many sizes and can be within a range from about 2 mm to about 4 mm, for example. The device may comprise a substantially fixed diameter, or alternatively can be expandable, and may comprise fixed or expandable retention structures, as described herein.

TABLE 6D Frit OD (mm) 1 0.5 Frit Length (mm) 1 1 Frit Vol. (uL) 0.785 0.19625 Vol Res (uL) 0.4 2 4 8 16 27 31 39 63 110 157 Vol Frit (uL) 0.19625 0.19625 0.785 0.785 0.785 0.785 0.785 0.785 0.785 0.785 0.785 Vol Device (uL) 0.59625 2.19625 4.785 8.785 16.785 27.785 31.785 39.785 63.785 110.785 157.785 Radius squared 0.09 0.3 0.4 0.7 1.3 2.2 2.5 3.2 5.1 8.8 12.6 Radius (mm) 0.3 0.5 0.6 0.8 1.2 1.5 1.6 1.8 2.3 3.0 3.5 OD (mm) 0.6(4) 1.1(3) 1.2(3) 1.7(3) 2.3(3) 3.0(2) 3.2(2) 3.6(2) 4.5(2) 5.9(2) 7.1(2) Dev Length 2.0(6) 2.5(5) 4.0(1) 4.0(1) 4.0(1) 4.0(1) 4.0(1) 4.0(1) 4.0(1) 4.0(1) 4.0(1) (mm) (1)Fixed penetration upper limit (2)May use non simple cylinder design to decrease incision length, for example expandable reservoir (3)OD accommodates 1 mm diameter porous frit structure and satisfies incision length limit (4)Device OD may use a smaller porous frit structure (5)Length reduced to drive OD to accommodate porous frit structure (6)Length reduced to drive OD to accommodate porous frit structure, and Device OD may use smaller frit

Example 15A Calculation and Measurement of Small Release Rate Profiles as a Model for a Therapeutic Agent Released Through the Porous Frit Structure

Studies of the release of fluorescein from reservoirs through porous frit structures were conducted so as to determine the release of small molecule drugs through the porous frit structure. The fluorescein model shows that the porous frit structures and reservoirs as described herein are suitable for use with small molecule drug deliver. The release profiles of Avastin™, Lucentis™ and BSA in conjunction with the fluorescein data show that the porous frit structures and reservoirs can be used for sustained release of many drugs, molecules and therapeutic agents of many molecular weights and sizes.

FIG. 25A shows cumulative release for fluorescein through a 0.2 media grade porous fit structure. The experiment used: 2 mg/mL Fluorescein sodium; Frit #2 (0.031×0.049″, media grade 0.2 um, 316L SS, Mott Corporation); Machined polycarbonate surrogate with screw; 37C. The fluorescein samples were assayed by UV absorbance at 492 nm with a plate reader. The determined RRI based on measurements is 0.02, consistent with the model for release of the therapeutic agents as described herein.

FIG. 25A-1 shows cumulative release to about 90 days for fluorescein through a 0.2 media grade porous fit structure as in FIG. 25A. The mean RRI based upon the first four data points was 0.02 mm. The mean RRI to release for 90 days (excluding the first point) is 0.026 mm. These data show stability of the rate of release and that the porous frit structure can be used for small molecule delivery or large molecule delivery, or combinations thereof.

FIG. 25B shows rate of release as in FIG. 25A. The release rate data show a rate of release from about 1.0 ug per day to about 1.8 ug per day. Although the initial release rate at the first day is slightly lower than subsequent rates, the rate of release is sufficiently high to provide therapeutic effect in accordance with the drug release model. Although there can be an initial period of about a day for the release rate profile to develop, possibly related to wetting of the interconnecting channels of the porous structure, the release rate profile corresponds substantially to the release rate index (RRI) of 0.02. Based on the teachings described herein, a person of ordinary skill in the art could determine the release rate profile with additional data for an extended time of at least about one month, for example at least about three months, six months or more, so as to determine the release rate profile for an extended time.

FIG. 25B-1 shows rate of release as in FIG. 25A-1.

Example 15B Measured Release Rate Profiles for Lucentis™ Through the Porous Frit Structures

The experiments used: 10 mg/mL Lucentis™; Machined poly(methyl methacrylate) surrogate with screw; and a Reservoir Volume 30 uL; 37C. All porous frit structures are 316L SS, Mott Corporation. Data shown are measured data from all devices except for a few samples that showed either bubble growth or low receiver volume.

Table 6E shows results for 39 out of 48 devices were included in the table and graphs shown below. The data from the in vitro studies shown in Table 6E show that Lucentis™ can be delivered with the device having porous frit structure. The diameter ranged from 0.031″ to 0.038″, and the length ranged from 0.029 to 0.049. The media grade ranged from 0.1 to 0.3, and the RRI ranged from 0.014 to 0.090. The data show very low variability suitable in in vivo human treatment, with the % CV below 10% in all instances, and less than 3% for four of five device configurations measured.

Although some of the measurements were excluded, this exclusion is appropriate and associated with in vitro testing conditions that differ substantially from the in vivo model. Five devices were excluded due to bubble growth (10%), and four were excluded due to receiver volume issues at one timepoint for that device (8%). The latter can be an experimental error associated with the volume of the receiver below the assumed value due to evaporation from inadequately sealed vials or due to pipetting error. In some instances the in vitro experimental test apparatus can be sensitive to bubble formation that may differ substantially from the in vivo model as the living eye can resorb oxygen from the therapeutic devices. Bubbles can form as receiver fluid is heated to 37° C. and gas concentrations are greater than their solubilities at 37° C. To minimize the occurrence of bubble formation, receiver solutions were degassed before insertion of the devices. These experimental in vitro studies suggest that degassing of samples can be helpful with the in vitro assays.

TABLE 6E Frit Media Dimensions Grade RRI Number of Dia Length (μm)  (mm) % CV Replicates 0.038″ 0.029″ 0.3 0.090 2.1% 6 0.038″ 0.029″ 0.2 0.061 2.8% 14 0.038″ 0.029″ 0.1 0.039 2.3% 5 0.031″ 0.049″ 0.2 0.021 9.9% 12 0.031″ 0.049″ 0.1 0.014 2.5% 2

FIG. 25C shows cumulative release to about thirty days for Lucentis™ through a 0.2 media grade porous fit structure having a diameter of 0.038 in and a length (thickness) of 0.029, corresponding to a release rate of 0.061 as shown in the second row of Table 6E.

FIG. 25D shows rates of release of the devices as in FIG. 25C.

FIG. 25E shows cumulative release to about thirty days for Lucentis™ for 30 uL devices having a RRI's from about 0.090 to about 0.015.

FIG. 25F shows rates of release of the devices as in FIG. 25E.

These above experimentally measured data show stable release of the Lucentis™ for 30 days for a wide range of frit diameters, thicknesses and media grades consistent with the release rate model of the porous structure and reservoir as described herein. For example, the media grade, thickness, diameter and reservoir volume can be tuned to provide sustained release for a predetermined period of time above a predetermined targeted minimum inhibitory concentration. When combined with the Avastin™ and Fluorescein data, these data show that stable release can be achieved for extended times for many therapeutic agents consistent with the release model as described herein.

Example 16 Scanning Electron Micrographs of Porous Frit Structures

FIGS. 26A and 26B show scanning electron microscope images from fractured edges of porous fit structures of 0.2 media grade and 0.5 media grade porous material, respectively. The commercially available samples were obtained from Mott Corporation and comprised 316L stainless steel. The samples were mechanically fractured so as to show the porous structure and interconnecting channels within the material to release the therapeutic agent. The micrograph images show a plurality of interconnecting channels disposed between openings of the first surface and openings of the second surface.

FIGS. 27A and 27B show scanning electron microscope images from surfaces of porous fit structures of media grade of 0.2 and 0.5, respectively, from the samples of FIGS. 26A and 26B. The images show a plurality of openings on the surface connected with interconnecting channels as in FIGS. 26A and 26B.

Example 17 Porous Frit Structure Mechanical Flow Testing to Identify Porous Frit Structures Suitable for Use with Therapeutic Agent Delivery Devices

The relative characteristics of sample elements can be determined by subjecting the fit to a number of mechanical tests, including but not limited to pressure decay and flow. These tests can be combined with drug release rate information, for example the RRI, so as to determine the release profile of the devices. These tests can be used with the porous structure positioned on the therapeutic device, so as to quantify flow through the porous structure of the device and determine suitable of the porous structure. Similar tests can be used to quantify the porous structure prior to mounting on the therapeutic device. At least some of the therapeutic devices can be evaluated with the gas flow of the porous structure mounted on a partially assembled therapeutic device, for example as a quality control check. In some embodiments, the flow test can be performed on the partially assembled or substantially assembled therapeutic device prior to insertion of the therapeutic agent into the reservoir and prior to insertion into the patient, so as to ensure that the porous structure is suitable for release of the therapeutic agent and affixed to the device, for example a support of the therapeutic device.

These tests may utilize a variety of working fluids, but will most likely use a readily available gas such as air or nitrogen. To date, flow and pressure decay tests have been used to identify different frit characteristics that may be correlated to other test results such as chemical or pharmacologic performance.

Fixturing

Each of the test methods above may use a mechanical connection of the test specimen to the test hardware and a number of techniques have been explored and employed. These fixtures include a both a means of reliably securing the specimen (such as heat recoverable tubing, elastic tubing, press fits into relatively rigid components, etc.) and a means of coupling (such as a luer, barbed fitting, quick connect coupling, etc.) that allow convenient and repeatable attachment to the test hardware.

Test Hardware

Each of the desired tests can be developed using commercially available solutions, or by assembling readily available instrumentation to create a custom test arrangement. Again, both of these approaches have been evaluated. A working system will consist of a means for connecting a test specimen, a controllable source (usually, but not limited to pressure), a manometer (or other pressure measurement device), and one or more transducers (pressure, flow, etc.) used to measure the test conditions and/or gather data for further analysis.

Example 17A Pressure Decay Test to Identify Porous Structures Suitable for Use with Therapeutic Drug Delivery Devices

FIG. 28 shows a pressure decay test and test apparatus for use with a porous structure so as to identify porous frit structures suitable for use with therapeutic devices in accordance with embodiments described herein.

One method of pressure decay testing is performed with the hardware shown schematically in FIG. 28. An initial pressure is applied to the system by an outside source such as a syringe, compressed air, compressed nitrogen, etc. The manometer may be configured to display simply the source gage pressure, or the actual differential pressure across the specimen. One side of the fixtured specimen is normally open to atmosphere, creating a pressure which will decay at a rate determined by the properties of the frit being tested. The instantaneous pressure may be measured by a pressure transducer that converts and supplies a signal to a data acquisition module (DAQ) that transfers data to a computer. The rate of pressure drop is then recorded and can be used for comparison to the performance of other frits or an acceptability requirement/specification. This comparison may be made by grossly comparing the pressure at a given time, or by directly comparing the output pressure decay curves.

An example test procedure would pressurize the system to slightly greater than 400 mmHg as displayed by the manometer. The computer and DAQ are configured to begin data acquisition as the pressure drops below 400 mmHg, and a data point is taken approximately every 0.109 seconds. While the test can be stopped at any time, it is likely that standard discreet points along the course of pressure decay data would be selected so as to allow direct comparison of fit flow performance (e.g. time for decay from 400 mmHg to 300 mmHg, and from 400 mmHg to 200 mmHg.)

Example 17B Pressure Decay Test to Identify Porous Structures Suitable for Use with Therapeutic Drug Delivery Devices

FIG. 29 shows a pressure flow test and test apparatus suitable for use with a porous structure so as to identify porous frit structures suitable for use with therapeutic devices in accordance with embodiments described herein.

Using a similar hardware set-up, flow thru the test specimen can also be characterized. In this test, the source pressure is constantly regulated to a known pressure and the flow of a working fluid is allowed to flow thru a mass flow meter and then thru the fixtured test fit. As in the pressure decay test, the specific characteristics of the frit determine that rate at which the working fluid will flow through the system. For additional accuracy, pressure at the otherwise open end of the fixture test frit may be regulated to control the backpressure, and therefore the pressure drop across the specimen.

Flow testing may have advantages over pressure decay testing due to the instantaneous nature of the method. Rather than waiting for the pressure to drop, the flow thru a sample should stabilize quickly enabling testing of large number of samples to be performed in rapid fashion.

In an example test procedure, a regulated compressed cylinder would supply the system with a constant source pressure of 30 psig and a constant back pressure of 1 psig. The test fluid would flow through the test frit at a characteristic rate (which is dependent on the pressure, but is expected to be in the 10-500 sccm range) as measured by the mass flow meter.

Example 17C Determination of Therapeutic Release Rate Based on Gas Flow

Table 7 shows a table that can be used to determine release of therapeutic agent, for example the RRI, based on the flow of a gas such as oxygen or nitrogen through the porous structure. The flow through the porous structure can be measured with a decay time of the gas pressure, for with the flow rate across the porous structure with a pressure drop across the porous fit structure, as described herein. The flow rate and RRI can be determined based on the media grade of the material, for example as commercially available media grade material available from Mott Corp. The therapeutic agent can be measured through the porous structure, or a similar test molecule. The initial measurements measured the RRI for Avastin™ with the porous fit structures shown. Based on the teachings described herein, a person of ordinary skill in the art can conduct experiments to determine empirically the correspondence of flow rate with a gas to the release rate of the therapeutic agent.

TABLE 7 Media Length Grade O.D. (in.) (in.) RRI Flow 300 Decay 200 Decay 0.2 0.031 0.049 0.019 106 256 0.2 0.038 0.029 0.034 0.1 0.038 0.029 0.014 81 201 0.2 0.038 0.029 0.033 31 78

The above partially populated table shows the amount and nature of fit data that can collected. It is contemplated to use some form of non-destructive testing (i.e. not drug release testing) so as to enable:

a) QC receiving inspection testing of frits b) QC final device assembly testing

One of ordinary skill can demonstrate a correlation between one or more “flow” tests and the actual drug release testing which relies on diffusion rather than forced gas flow. The data suggests that flow testing of frits can be both repeatable and falls in line with expectations.

Preliminary testing also indicates that the test for the frit alone can be substantially similar to the frit as an assembled device.

Any structure or combination of structures or method steps or components or combinations thereof as described herein can be combined in accordance with embodiments as described herein, based on the knowledge of one of ordinary skill in the art and teachings described herein. In addition, any structure or combination of structures or method steps or components or combinations thereof as described herein may be specifically excluded from any embodiments, based on the knowledge of one of ordinary skill in the art and the teachings described herein.

While the exemplary embodiments have been described in some detail, by way of example and for clarity of understanding, those of skill in the art will recognize that a variety of modifications, adaptations, and changes may be employed. Hence, the scope of the present invention should be limited solely by the appended claims.

TABLE 1A Therapeutic Agent List Molecular Generic Name Brands (Companies) Category Indication Weight 2-Methoxyestradiol (Paloma Pharmaceuticals) Angiogenesis inhibitors AMD analogs 3-aminothalidomide 13-cis retinoic acid Accutane TM (Roche Pharmaceuticals) A0003 (Aqumen BioPharmaceuticals) A0003 AMD A5b1 integrin (Jerini Ophthalmic); (Ophthotech) Inhibitors of a5b1 integrin AMD inhibitor Abarelix Plenaxis ™ (Praecis Pharmaceuticals) Anti-Testosterone Agents; For palliative treatment of advanced 37731 Antineoplastic Agents prostate cancer. Abatacept Orencia ™ (Bristol-Myers Squibb) Antirheumatic Agents For the second line reduction of the signs 37697 and symptoms of moderate-to-severe active rheumatoid arthritis, inducing inducing major clinical response, slowing the progression of structural damage, and improving physical function in adult patients who have Abciximab ReoPro ™; ReoPro ™ (Centocor) Anticoagulants; For treatment of myocardial infarction, 42632 Antiplatelet Agents adjunct to percutaneous 134oronary intervention, unstable angina ABT-578 (Abbott Laboratories) Limus Immunophilin Binding Compounds Acetonide Adalimumab Humira ™ (Abbott Laboratories) Antirheumatic Agents; Uveitis, AMD 25645 Immunomodulatory Agents Aldesleukin Proleukin ™; Proleukin ™ (Chiron Antineoplastic Agents For treatment of adults with metastatic 61118 Corp) renal cell carcinoma Alefacept Amevive ™ Immunomodulatory For treatment of moderate to severe 42632 Agents; chronic plaque psoriasis Immunosuppressive Agents Alemtuzumab Campath ™; Campath ™ (ILEX Antineoplastic Agents For treatment of B-cell chronic 6614 Pharmaceuticals LP); MabCampath ™ lymphocytic leukemia Alpha-1-proteinase Aralast ™ (Baxter); Prolastin ™ Enzyme Replacement For treatment of panacinar emphysema 28518 inhibitor (Talecris Biotherapeutics C formerly Agents Bayer) Alteplase Activase ™ (Genentech Inc) Thrombolytic Agents For management of acute myocardial 54732 infarction, acute ischemic strok and for lysis of acute pulmonary emboli AMG-1470 Anakinra Kineret ™ (Amgen Inc) Anti-Inflammatory Agents, For the treatment of adult rheumatoid 65403 Non-Steroidal; arthritis. Antirheumatic Agents; Immunomodulatory Agents Anecortave acetate Angiostatin Anistreplase Eminase ™ (Wulfing Pharma GmbH) Thrombolytic Agents For lysis of acute pulmonary emboli, 54732 intracoronary emboli and management of myocardial infarction Anti-angiogenesis (Eyecopharm) Anti-angiogenesis AMD peptides peptides Anti-angiogenesis (TRACON Pharma) Anti-angiogenesis AMD antibodies, antibodies TRC093, TRC105 Anti-angiogeric Icon-1 ™ (Iconic Therapeutics) Anti-angiogeric AMD bifunctional protein bifunctional protein, Icon-1 Anti-endothelial growth factor Antihemophilic Advate ™; Alphanate ™; Bioclate ™; Coagulants; Thrombotic For the treatment of hemophilia A, von 70037 Factor Helixate ™; Helixate FS ™; Hemofil Agents Willebrand diseae and Factor XIII M ™; Humate-P ™; Hyate:C ™; Koate- deficiency HP ™; Kogenate ™; Kogenate FS ™; Monarc-M ™; Monoclate-P ™; ReFacto ™; Xyntha ™ Antithymocyte Genzyme); Thymoglobulin ™ Immunomodulatory Agents For prevention of renal transplant 37173 globulin (SangStat Medical rejection Anti-hypertensive (MacuCLEAR) Anti-hypertensive MC1101 AMD MC1101 Anti-platelet devired growth factor Anti-VEGF (Neurotech); Avastin ™ (NeoVista) Anti-VEGF AMD AP23841 (Ariad) Limus Immunophilin Binding Compounds Aprotinin Trasylol ™ Antifibrinolytic Agents For prophylactic use to reduce 90569 perioperative blood loss and the need for blood transfusion in patients undergoing cardiopulmonary bypass in the course of coronary artery bypass graft surgery who are at an increased risk for blood loss and blood transfusio Arcitumomab CEA-Scan ™ Diagnostic Agents; For imaging colorectal tumors 57561 Imaging Agents Asparaginase Elspar ™ (Merck & Co. Inc) Antineoplastic Agents For treatment of acute lympocytic 132.118 leukemia and non-Hodgkins lymphoma Axitinib Tyrosine Kinase Inhibitors 386 Basiliximab Simulect ™ (Novartis Immunomodulatory For prophylactic treatment of kidney 61118 Pharmaceuticals) Agents; transplant rejection Immunosuppressive Agents Becaplermin Regranex ™; Regranex ™ (OMJ Anti-Ulcer Agents; Topical For topical treatment of skin ulcers (from 123969 Pharmaceuticals) diabetes) Bevacizumab Avastin ™; Avastin ™ (Genentech Inc) Antiangiogenesis Agents; For treatment of metastatic colorectal 27043 Antineoplastic Agents cancer Bivalirudin Angiomax ™; Angiomax ™ (Medicines Anticoagulants; For treatment of heparin-induced 70037 Co or MDCO); Angiox ™ Antithrombotic Agents thrombocytopenia Bortezomib Proteosome Inhibitors Bosutinib Tyrosine Kinase Inhibitors 530 Botulinum Toxin BOTOX ™ (Allegran Inc); BOTOX Anti-Wrinkle Agents; For the treatment of cervical dystonia in 23315 Type A Cosmetic ™ (Allegran Inc); Botox ™; Antidystonic Agents; adults to decrease the severity of Dysport ™ Neuromuscular Blocking abnormal head position and neck pain Agents associated with cervical dystonia. Also for the treatment of severe primary axillary hyperhidrosis that is inadequately managed with topical Botulinum Toxin Myobloc ™ (Solstice Neurosciences); Antidystonic Agents For the treatment of patients with cervical 12902 Type B Neurobloc ™ (Solstice Neurosciences) dystonia to reduce the severity of abnormal head position and neck pain associated with cervical dystonia. C5 inhibitor (Jerini Ophthalmic); (Ophthotech) Inhibitors of C5 AMD Canstatin Capromab ProstaScint ™ (Cytogen Corp) Imaging Agents For diagnosis of prostate cancer and 84331 detection of intra-pelvic metastases Captopril ACE Inhibitors CCI-779 (Wyeth) Limus Immunophilin Binding Compounds Cediranib Tyrosine Kinase Inhibitors 450 Celecoxib Cyclooxygenase Inhibitors Cetrorelix Cetrotide ™ Hormone Antagonists; For the inhibition of premature LH surges 78617 Infertility Agents in women undergoing controlled ovarian stimulation Cetuximab Erbitux ™; Erbitux ™ (ImClone Antineoplastic Agents For treatment of metastatic colorectal 42632 Systems Inc) cancer. Choriogonadotropin Novarel ™; Ovidrel ™; Pregnyl ™; Fertility Agents; For the treatment of female infertility 78617 alfa Profasi ™ Gonadotropins Cilary neurotrophic (Neurotech) Cilary neurotrophic factor AMD factor Coagulation Factor Benefix ™ (Genetics Institute) Coagulants; Thrombotic For treatment of hemophilia (Christmas 267012 IX Agents disease). Coagulation factor NovoSeven ™ (Novo Nordisk) Coagulants; Thrombotic For treatment of hemorrhagic 54732 VIIa Agents complications in hemophilia A and B Colchicines Collagenase Cordase ™; Santyl ™ (Advance Anti-Ulcer Agents; Topical For treatment of chronic dermal ulcers 138885 Biofactures Corp); Xiaflextm ™ and severe skin burns Complement factor (Optherion); (Taligen Therapeutics) Complement factor H AMD, Geographic Atrophy H recombinant recombinant Compstatin (Potentia Pharmaceuticals) Complement Factor C3 AMD derivative peptide, Inhibitors; Compstatin POT-4 Derivative Peptides Corticotropin ACTH ™; Acethropan ™; Acortan ™; Diagnostic Agents For use as a diagnostic agent in the 33927 Acthar ™; Exacthin ™; H.P. Acthar screening of patients presumed to have Gel ™; Isactid ™; Purified cortrophin adrenocortical insufficiency. gel ™; Reacthin ™; Solacthyl ™; Tubex Cosyntropin Cortrosyn ™; Synacthen depot ™ Diagnostic Agents For use as a diagnostic agent in the 33927 screening of patients presumed to have adrenocortical insufficiency. Cyclophilins Limus Immunophilin Binding Compounds Cyclosporine Gengraf ™ (Abbott labs); Neoral ™ Antifungal Agents; For treatment of transplant rejection, 32953 (Novartis); Restasis ™; Restasis ™ Antirheumatic Agents; rheumatoid arthritis, severe psoriasis (Allergan Inc); Sandimmune ™ Dermatologic Agents; (Novartis); Sangcya ™ Enzyme Inhibitors; Immunomodulatory Agents; Immunosuppressive Agents Daclizumab Zenapax ™ (Hoffmann-La Roche Inc) Immunomodulatory For prevention of renal transplant 61118 Agents; rejection Immunosuppressive Agents Darbepoetin alfa Aranesp ™ (Amgen Inc.) Antianemic Agents For the treatment of anemia (from renal 55066 transplants or certain HIV treatment) Dasatinib Tyrosine Kinase Inhibitors 488 Defibrotide Dasovas ™; Noravid ™; Prociclide ™ Antithrombotic Agents Defibrotide is used to treat or prevent a 36512 failure of normal blood flow (occlusive venous disease, OVD) in the liver of patients who have had bone marrow transplants or received certain drugs such as oral estrogens, mercaptopurine, and many others. Denileukin diftitox Ontak ™ Antineoplastic Agents For treatment of cutaneous T-cell 61118 lymphoma Desmopressin Adiuretin ™; Concentraid ™; Stimate ™ Antidiuretic Agents; For the management of primary nocturnal 46800 Hemostatics; Renal enuresis and indicated as antidiuretic Agents replacement therapy in the management of central diabetes insipidus and for the management of the temporary polyuria and polydipsia following head trauma or surgery in the pitu Dexamethasone Ozurdex ™ (Allergan) Glucocorticoid DME, inflammation, macular edema 392 following branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO) Diclofenac Cyclooxygenase Inhibitors Dithiocarbamate NFκB Inhibitor Dornase Alfa Dilor ™; Dilor-400 ™; Lufyllin ™; Enzyme Replacement For the treatment of cystic fibrosis. 7656 (double Lufyllin-400 ™; Neothylline ™; Agents strand) Pulmozyme ™ (Genentech Inc) Drotrecogin alfa Xigris ™; Xigris ™ (Eli Lilly & Co) Antisepsis Agents For treatment of severe sepsis 267012 Eculizumab Soliris ™; Soliris ™ (Alexion Complement Cascade AMD. 188333 Pharmaceuticals) Inhibitor (Factor C5) Efalizumab Raptiva ™; Raptiva ™ (Genentech Inc) Immunomodulatory For the treatment of adult patients with 128771 Agents; moderate to severe chronic plaque Immunosuppressive psoriasis, who are candidates for Agents phototherapy or systemic therapy. Endostatin Enfuvirtide Fuzeon ™; Fuzeon ™ (Roche Anti-HIV Agents; HIV For treatment of HIV AIDS 16768 Pharmaceuticals) Fusion Inhibitors Epoetin alfa Epogen ™ (Amgen Inc.); Epogin ™ Antianemic Agents For treatment of anemia (from renal 55066 (Chugai); Epomax ™ (Elanex); transplants or certain HIV treatment) Eprex ™ (Janssen-Cilag. Ortho Biologics LLC); NeoRecormon ™ (Roche); Procrit ™ (Ortho Biotech); Recormon ™ (Roche) Eptifibatide Integrilin ™; Integrilin ™ (Millennium Anticoagulants; For treatment of myocardial infarction and 7128 Pharm) Antiplatelet Agents; acute coronary syndrome. Platelet Aggregation Inhibitors Erlotinib Tyrosine Kinase Inhibitors 393 Etanercept Enbrel ™; Enbrel ™ (Immunex Corp) Antirheumatic Agents; Uveitis, AMD 25645 Immunomodulatory Agents Everolimus Limus Immunophilin Binding Compounds Exenatide Byetta ™; Byetta ™ (Amylin/Eli Lilly) Indicated as adjunctive therapy to 53060 improve glycemic control in patients with Type 2 diabetes mellitus who are taking metformin, a sulfonylurea, or a combination of both, but have not achieved adequate glycemic control. FCFD4514S Genentech/Roche Complement Cascade AMD, Geographic Atrophy Inhibitor (Factor D) Felypressin Felipresina ™ [INN-Spanish]; Renal Agents; For use as an alternative to adrenaline as 46800 Felipressina ™ [DCIT]; Felypressin ™ Vasoconstrictor Agents a 143ocalizing agent, provided that local [USAN:BAN:INN]; Felypressine ™ ischaemia is not essential. [INN-French]; Felypressinum ™ [INN- Latin]; Octapressin ™ Fenretinide (Sirion Therapeutics) Binding Protein Antagonist AMD for Oral Vitamin A Filgrastim Neupogen ™ (Amgen Inc.) Anti-Infective Agents; Increases leukocyte production, for 28518 Antineutropenic Agents; treatment in non-myeloid Immunomodulatory Agents cancer, neutropenia and bone marrow transplant FK605-binding Limus Immunophilin proteins, FKBPs Binding Compounds Fluocinolone Retisert ™ (Bausch & Lomb); Iluvien ™ Glucocorticoid Retinal inflammation, diabetic macular 453 Acetonide (Alimera Sciences, Inc.) edema Follitropin beta Follistim ™ (Organon); Gonal F ™; Fertility Agents For treatment of female infertility 78296 Gonal-F ™ Fumagillin Galsulfase Naglazyme ™; Naglazyme ™ Enzyme Replacement For the treatment of adults and children 47047 (BioMarin Pharmaceuticals) Agents with Mucopolysaccharidosis VI. Gefitinib Tyrosine Kinase Inhibitors 447 Gemtuzumab Mylotarg ™; Mylotarg ™ (Wyeth) Antineoplastic Agents For treatment of acute myeloid leukemia 39826 ozogamicin Glatiramer Acetate Copaxone ™ Adjuvants, Immunologic; For reduction of the frequency of relapses 29914 Immunosuppressive in patients with Relapsing-Remitting Agents Multiple Sclerosis. Glucagon GlucaGen ™ (Novo Nordisk); Antihypoglycemic Agents For treatment of severe hypoglycemia, 54009 recombinant Glucagon ™ (Eli Lilly) also used in gastrointestinal imaging Goserelin Zoladex ™ Antineoplastic Agents; Breast cancer; Prostate carcinoma; 78617 Antineoplastic Agents, Endometriosis Hormonal Human Serum Albutein ™ (Alpha Therapeutic Corp) Serum substitutes For treatment of severe blood loss, 39000 Albumin hypervolemia, hypoproteinemia Hyaluronidase Vitragan ™; Vitrase ™; Vitrase ™ (Ista Anesthetic Adjuvants; For increase of absorption and distribution 69367 Pharma) Permeabilizing Agents of other injected drugs and for rehydration Ibritumomab Zevalin ™ (IDEC Pharmaceuticals) Antineoplastic Agents For treatment of non-Hodgkin's 33078 lymphoma Idursulfase Elaprase ™ (Shire Pharmaceuticals) Enzyme Replacement For the treatment of Hunter syndrome in 47047 Agents adults and children ages 5 and older. Imatinib Tyrosine Kinase Inhibitors AMD, DME 494 Immune globulin Civacir ™; Flebogamma ™ (Instituto Anti-Infectives; For treatment of immunodeficiencies, 42632 Grifols SA); Gamunex ™ (Talecris Immunomodulatory Agents thrombocytopenic purpura, Kawasaki Biotherapeutics) disease, gammablobulinemia, leukemia, bone transplant Infliximab Remicade ™ (Centocor Inc) Immunomodulatory Uveitis, AMD 25645 Agents; Immunosuppressive Agents Insulin Glargine Lantus ™ Hypoglycemic Agents For treatment of diabetes (type I and II) 156308 recombinant Insulin Lyspro Humalog ™ (Eli Lily); Insulin Lispro Hypoglycemic Agents For treatment of diabetes (type I and II) 154795 recombinant (Eli Lily) Insulin recombinant Novolin R ™ (Novo Nordisk) Hypoglycemic Agents For treatment of diabetes (type I and II) 156308 Insulin, porcine Iletin II ™ Hypoglycemic Agents For the treatment of diabetes (type I and 156308 II) Interferon Interferon Alfa-2a, Roferon A ™ (Hoffmann-La Roche Antineoplastic Agents; For treatment of chronic hepatitis C, hairy 57759 Recombinant Inc); Veldona ™ (Amarillo Antiviral Agents cell leukemia, AIDS-related Kaposi's Biosciences) sarcoma, and chronic myelogenous leukemia. Also for the treatment of oral warts arising from HIV infection. Interferon Alfa-2b, Intron A ™ (Schering Corp) Antineoplastic Agents; For the treatment of hairy cell leukemia, 57759 Recombinant Antiviral Agents; malignant melanoma, and AIDS-related Immunomodulatory Agents Kaposi's sarcoma. Interferon alfacon-1 Advaferon ™; Infergen ™ (InterMune Antineoplastic Agents; For treatment of hairy cell leukemia, 57759 Inc) Antiviral Agents; malignant melanoma, and AIDS-related Immunomodulatory Agents Kaposi's sarcoma Interferon alfa-n1 Wellferon ™ (GlaxoSmithKline) Antiviral Agents; For treatment of venereal or genital warts 57759 Immunomodulatory Agents caused by the Human Papiloma Virus Interferon alfa-n3 Alferon ™ (Interferon Sciences Inc.); Antineoplastic Agents; For the intralesional treatment of 57759 Alferon LDO ™; Alferon N Injection ™ Antiviral Agents; refractory or recurring external Immunomodulatory Agents condylomata 147cuminate. Interferon beta-1b Betaseron ™ (Chiron Corp) Antiviral Agents; For treatment of relapsing/remitting 57759 Immunomodulatory Agents multiple sclerosis Interferon gamma- Actimmune ™; Actimmune ™ Antiviral Agents; For treatment of Chronic granulomatous 37835 1b (InterMune Inc) Immunomodulatory Agents disease, Osteopetrosis Lapatinib Tyrosine Kinase Inhibitors 581 Lepirudin Refludan ™ Anticoagulants; For the treatment of heparin-induced 70037 Antithrombotic Agents; thrombocytopenia Fibrinolytic Agents Lestaurtinib Tyrosine Kinase Inhibitors 439 Leuprolide Eligard ™ (Atrix Labs/QLT Inc) Anti-Estrogen Agents; For treatment of prostate cancer, 37731 Antineoplastic Agents endometriosis, uterine fibroids and premature puberty Lutropin alfa Luveris ™ (Serono) Fertility Agents For treatment of female infertility 78617 Mecasermin Increlex ™; Increlex ™ (Tercica); Iplex For the long-term treatment of growth 154795 failure in pediatric patients with Primary IGFD or with GH gene deletion who have developed neutralizing antibodies to GH. It is not indicated to treat Secondary IGFD resulting from GH deficiency, malnutrition, hypoth Menotropins Repronex ™ Fertility Agents For treatment of female infertility 78617 Methotrexate Immunomodulatory Uveitis, DME mTOR inhibitors Muromonab Orthoclone OKT3 ™ (Ortho Biotech) Immunomodulatory For treatment of organ transplant 23148 Agents; recipients, prevention of organ rejection Immunosuppressive Agents Natalizumab Tysabri ™ Immunomodulatory Agents For treatment of multiple sclerosis. 115334 Nepafenac Cyclooxygenase Inhibitors Nesiritide Natrecor ™ Cardiac drugs For the intravenous treatment of patients 118921 with acutely decompensated congestive heart failure who have dyspnea at rest or with minimal activity. Nilotinib Tyrosine Kinase Inhibitors 530 NS398 Cyclooxygenase Inhibitors Octreotide Atrigel ™; Longastatin ™; Anabolic Agents; For treatment of acromegaly and 42687 Sandostatin ™; Sandostatin LAR ™; Antineoplastic Agents, reduction of side effects from cancer Sandostatin LAR ™ (Novartis) Hormonal; Gastrointestinal chemotherapy Agents; Hormone Replacement Agents Omalizumab Xolair ™ (Genentech Inc) Anti-Asthmatic Agents; For treatment of asthma caused by 29596 Immunomodulatory Agents allergies Oprelvekin Neumega ™; Neumega ™ (Genetics Coagulants; Thrombotics Increases reduced platelet levels due to 45223 Institute Inc) chemotherapy OspA lipoprotein LYMErix ™ (SmithKline Beecham) Vaccines For prophylactic treatment of Lyme 95348 Disease OT-551 (Othera) Anti-oxidant eyedrop AMD Oxytocin Oxytocin ™ (BAM Biotech); Pitocin ™ Anti-tocolytic Agents; To assist in labor, elective labor induction, 12722 (Parke-Davis); Syntocinon ™ (Sandoz) Labor Induction Agents; uterine contraction induction Oxytocics Palifermin Kepivance ™ (Amgen Inc) Antimucositis Agents For treatment of mucositis (mouth sores) 138885 Palivizumab Synagis ™ Antiviral Agents For treatment of respiratory diseases 63689 casued by respiratory syncytial virus Panitumumab Vectibix ™; Vectibix ™ (Amgen) Antineoplastic Agents For the treatment of EGFR-expressing, 134279 metastatic colorectal carcinoma with disease progression on or following fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens. PDGF inhibitor (Jerini Ophthalmic); (Ophthotech) Inhibitors of PDGF AMD PEDF (pigment epithelium derived factor) Pegademase Adagen ™ (Enzon Inc.) Enzyme Replacement For treatment of adenosine deaminase 36512 bovine Agents deficiency Pegaptanib Macugen ™ Oligonucleotide For the treatment of neovascular (wet) 103121 age-related macular degeneration. Pegaspargase Oncaspar ™ (Enzon Inc) Antineoplastic Agents For treatment of acute lymphoblastic 132.118 leukemia Pegfilgrastim Neulasta ™ (Amgen Inc.) Anti-Infective Agents; Increases leukocyte production, for 28518 Antineutropenic Agents; treatment in non-myeloid cancer, Immunomodulatory Agents neutropenia and bone marrow transplant Peginterferon alfa- Pegasys ™ (Hoffman-La Roche Inc) Antineoplastic Agents; For treatment of hairy cell leukemia, 57759 2a Antiviral Agents; malignant melanoma, and AIDS-related Immunomodulatory Agents Kaposi's sarcoma. Peginterferon alfa- PEG-Intron (Schering Corp); Unitron Antineoplastic Agents; For the treatment of chronic hepatitis C in 57759 2b PEG ™ Antiviral Agents; patients not previously treated with Immunomodulatory Agents interferon alpha who have compensated liver disease and are at least 18 years of age. Pegvisomant Somavert ™ (Pfizer Inc) Anabolic Agents; Hormone For treatment of acromegaly 71500 Replacement Agents Pentoxifylline Perindozril ACE Inhibitors Pimecrolimus Limus Immunophilin Binding Compounds PKC (protein kinase C) inhibitors POT-4 Potentia/Alcon Complement Cascade AMD Inhibitor (Factor C3) Pramlintide Symlin ™; Symlin ™ (Amylin For the mealtime treatment of Type I and 16988 Pharmaceuticals) Type II diabetes in combination with standard insulin therapy, in patients who have failed to achieve adequate glucose control on insulin monotherapy. Proteosome Velcade ™ Proteosome inhibitors inhibitors Pyrrolidine Quinopril ACE Inhibitors Ranibizumab Lucentis ™ For the treatment of patients with 27043 neovascular (wet) age-related macular degeneration. Rapamycin (MacuSight) Limus Immunophilin AMD (siroliums) Binding Compounds Rasburicase Elitek ™; Elitek ™ (Sanofi-Synthelabo Antihyperuricemic Agents For treatment of hyperuricemia, reduces 168.11 Inc); Fasturtec ™ elevated plasma uric acid levels (from chemotherapy) Reteplase Retavase ™ (Centocor); Retavase ™ Thrombolytic Agents For lysis of acute pulmonary emboli, 54732 (Roche) intracoronary emboli and management of myocardial infarction Retinal stimulant Neurosolve ™ (Vitreoretinal Retinal stimulants AMD Technologies) Retinoid(s) Rituximab MabThera ™; Rituxan ™ Antineoplastic Agents For treatment of B-cell non-Hodgkins 33078 lymphoma (CD20 positive) RNAI (RNA interference of angiogenic factors) Rofecoxib Vioxx ™; Ceoxx ™; Ceeoxx ™ (Merck Cyclooxygenase Inhibitors & Co.) Rosiglitazone Thiazolidinediones Ruboxistaurin Eli Lilly Protein Kinase C (PKC)-b DME, diabetic peripheral retinopathy 469 Inhibitor Salmon Calcitonin Calcimar ™; Miacalcin ™ (Novartis) Antihypocalcemic Agents; For the treatment of post-menopausal 57304 Antiosteporotic Agents; osteoporosis Bone Density Conservation Agents SAR 1118 SARCode Immunomodulatory Agent Dry eye, DME, conjunctivitis Sargramostim Immunex ™; Leucomax ™ (Novartis); Anti-Infective Agents; For the treatment of cancer and bone 46207 Leukine ™; Leukine ™ (Berlex Antineoplastic Agents; marrow transplant Laboratories Inc) Immunomodulatory Agents SDZ-RAD Limus Immunophilin Binding Compounds Secretin SecreFlo ™; Secremax ™, SecreFlo ™ Diagnostic Agents For diagnosis of pancreatic exocrine 50207 (Repligen Corp) dysfunction and gastrinoma Selective inhibitor of the factor 3 complement cascade Selective inhibitor of the factor 5 complement cascade Semaxanib Tyrosine Kinase Inhibitors 238 Sermorelin Geref ™ (Serono Pharma) Anabolic Agents; Hormone For the treatment of dwarfism, prevention 47402 Replacement Agents of HIV-induced weight loss Serum albumin Megatope ™ (IsoTex Diagnostics) Imaging Agents For determination of total blood and 39000 iodinated plasma volumes SF1126 Semafore PI3k/mTOR Inhibition AMD, DME Sirolims (MacuSight) Limus Immunophilin AMD reformulation Binding Compounds (rapamycin) siRNA molecule (Quark Pharmaceuticals) siRNAi molecule synthetic AMD synthetic, FTP- 801i-14 Somatropin BioTropin ™ (Biotech General); Anabolic Agents; Hormone For treatment of dwarfism, acromegaly 71500 recombinant Genotropin ™ (Pfizer); Humatrope ™ Replacement Agents and prevention of HIV-induced weight (Eli Lilly); Norditropin ™ (Novo loss Nordisk); Nutropin ™ (Genentech Inc.); NutropinAQ ™ (Genentech Inc.); Protropin ™ (Genentech Inc.); Saizen ™ (Serono SA); Serostim ™; Serostim ™ (Serono SA); Tev- Tropin ™ (GATE) Squalamine Streptokinase Streptase ™ (Aventis Behringer Thrombolytic Agents For the treatment of acute evolving 90569 GmbH) transmural myocardial infarction, pulmonary embolism, deep vein thrombosis, arterial thrombosis or embolism and occlusion of arteriovenous cannulae Sunitinib Tyrosine Kinase Inhibitors 398 TA106 Taligen Complement Cascade AMD Inhibitor (Factor B) Tacrolimus Limus Immunophilin Binding Compounds Tenecteplase TNKase ™ (Genentech Inc) Thrombolytic Agents For treatment of myocardial infarction and 54732 lysis of intracoronary emboli Teriparatide Apthela ™; Forsteo ™; Forteo ™; Bone Density For the treatment of osteoporosis in men 66361 Fortessa ™; Opthia ™; Optia ™; Conservation Agents and postmenopausal women who are at Optiah ™; Zalectra ™; Zelletra ™ high risk for having a fracture. Also used to increase bone mass in men with primary or hypogonadal osteoporosis who are at high risk for fracture. Tetrathiomolybdate Thalidomide Celgene Anti-inflammatory, Anti- Uveitis proliferative Thyrotropin Alfa Thyrogen ™ (Genzyme Inc) Diagnostic Agents For detection of residueal or recurrent 86831 thyroid cancer Tie-1 and Tie-2 kinase inhibitors Toceranib Tyrosine Kinase Inhibitors 396 Tositumomab Bexxar ™ (Corixa Corp) Antineoplastic Agents For treatment of non-Hodgkin's 33078 lymphoma (CD20 positive, follicular) TPN 470 analogue Trastuzumab Herceptin ™ (Genentech) Antineoplastic Agents For treatment of HER2-positive 137912 pulmonary breast cancer Triamcinolone Triesence ™ Glucocorticoid DME, For treatment of inflammation 435 acetonide of the retina Troglitazone Thiazolidinediones Tumistatin Urofollitropin Fertinex ™ (Serono S.A.) Fertility Agents For treatment of female infertility 78296 Urokinase Abbokinase ™; Abbokinase ™ (Abbott Thrombolytic Agents For the treatment of 156ulmonary 90569 Laboratories) embolism, coronary artery thrombosis and IV catheter clearance Vandetanib Tyrosine Kinase Inhibitors 475 Vasopressin Pitressin ™; Pressyn ™ Antidiuretics; Oxytocics; For the treatment of enuresis, polyuria, 46800 Vasoconstrictor Agents diabetes insipidus, polydipsia and oesophageal varices with bleeding Vatalanib Tyrosine Kinase Inhibitors 347 VEGF receptor kinase inhibitor VEGF Trap Aflibercept ™ (Regneron Genetically Engineered DME, cancer, retinal vein occlusion, 96600 Pharmaceuticals, Bayer HealthCare Antibodies choroidal neovascularization, delay AG) wound healing, cancer treatment Visual Cycle (Acucela) Visual Cycle Modulator AMD Modulator ACU- 4229 Vitamin(s) Vitronectin receptor antagonists Volociximab Ophthotech alpha5beta1 Integrin AMD Inhibitor XL765 Exelixis/Sanofi-Aventis PI3k/mTOR Inhibition AMD, DME 

1.-74. (canceled)
 75. A therapeutic device to treat an eye, the device comprising: a rigid-walled housing having a substantially fixed volume during implantation and use, wherein the housing is sized to extend through the sclera into the vitreous humor when the device is implanted in the eye; a first chamber located within the housing and configured to hold a first therapeutic agent, the first chamber having a first rigid, porous structure positioned at a distal end region of the first chamber; and a second chamber located within the housing and configured to hold a second therapeutic agent, the second chamber having a second rigid, porous structure positioned at a distal end region of the second chamber; wherein at least one of the first and second chambers is refillable, and wherein the first and second rigid, porous structures each have a plurality of interconnecting, irregularly-shaped channels.
 76. The device of claim 75, wherein the first chamber has a first volume and the first rigid, porous structure has a first release rate index and a first porosity so as to release the first therapeutic agent in therapeutic amounts into the vitreous humor from the device for a first extended period of time when the device is implanted in the eye.
 77. The device of claim 76, wherein the first and second chambers are arranged in parallel, and wherein both the first and second chambers are refillable.
 78. The device of claim 77, wherein the first chamber is separated from the second chamber by a barrier extending through the housing from a proximal end region to a distal end region of the housing.
 79. The device of claim 78, further comprising a first injector configured to be coupled to the first chamber to deliver the first therapeutic agent into the first chamber.
 80. The device of claim 79, further comprising a second injector configured to be coupled to the second chamber to deliver the second therapeutic agent into the second chamber.
 81. The device of claim 80, wherein the second chamber has a second volume and the second rigid, porous structure has a second release rate index so as to release the second therapeutic agent in therapeutic amounts into the vitreous humor from the device for a second extended period of time when the device is implanted in the eye.
 82. The device of claim 76, wherein the first and second chambers are arranged in series.
 83. The device of claim 82, wherein the first chamber is separated from the second chamber by the first rigid, porous structure.
 84. The device of claim 83, further comprising a first injector coupled to the first chamber and configured to deliver the first therapeutic agent into the first chamber.
 85. The device of claim 84, wherein the second therapeutic agent within the second chamber is a solid.
 86. The device of claim 85, wherein the second chamber has a second volume and the second rigid, porous structure has a second release rate index and a second porosity so as to release the solid second therapeutic agent and first therapeutic agent.
 87. The device of claim 86, wherein the first release rate index and first porosity are smaller than the second release rate index and the second porosity, respectively, such that a release rate of the first therapeutic agent is determined based on the first porosity and first release rate index of the first porous structure and a release rate of the second therapeutic agent is determined based on the second porosity and second release rate index of the second porous structure.
 88. The device of claim 87, wherein the first therapeutic agent is released serially through the first porous structure followed by release through the second porous structure.
 89. The device of claim 85, wherein the second chamber comprises a sufficient amount of the solid second therapeutic agent such that the solid remains in the second chamber for a plurality of injections of the first therapeutic agent into the first chamber.
 90. The device of claim 89, wherein the solid second therapeutic agent remains in the second chamber for at least about one year when the device is implanted in the eye.
 91. The device of claim 75, wherein the first therapeutic comprises an antineoplastic agent and the second therapeutic comprises an anti-inflammatory agent.
 92. The device of claim 91, wherein the antineoplastic agent comprises a VEGF inhibitor and the anti-inflammatory agent comprises a non-steroidal anti-inflammatory agent.
 93. The device of claim 92, wherein the VEGF inhibitor is LUCENTIS.
 94. The device of claim 92, wherein the non-steroidal anti-inflammatory agent is a COX inhibitor.
 95. The device of claim 94, wherein the COX inhibitor is a water insoluble COX inhibitor.
 96. The device of claim 75, further comprising a proximal cap portion coupled near a proximal end region of the housing and adapted to be positioned outside the sclera when the device is implanted in the eye, the cap portion comprising a retention structure and a penetrable, non-permeable barrier.
 97. The device of claim 96, wherein the cap portion is adapted to receive an injection of at least the first therapeutic agent into the first chamber.
 98. The device of claim 97, wherein the penetrable, non-permeable barrier is configured to allow introduction of at least the first therapeutic agent into the first chamber without explanting the device during introduction of the first therapeutic agent the first chamber. 